Transgenic animals and cell lines for screening drugs effective for the treatment or prevention of Alzheimer&#39;s disease

ABSTRACT

Disclosed are transgenic animals and transfected cell lines expressing a protein associated with Alzheimer&#39;s Disease, neuroectodermal tumors, malignant astrocytomas, and glioblastomas. Also disclosed is the use of such transgenic animals and transfected cell lines to screen potential drug candidates for treating or preventing Alzheimer&#39;s disease, neuroectodermal tumors, malignant astrocytomas, and glioblastomas. The invention also relates to new antisense oligonucleotides, ribozymes, triplex forming DNA and external guide sequences that can be used to treat or prevent Alzheimer&#39;s disease, neuroectodermal tumors, malignant astrocytomas, and glioblastomas.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.09/380,203, filed Apr. 25, 2000, which is a 371 of PCT/US98/03685, filedFeb. 26, 1998 and published under PCT Article 21(2) in English on Sep.3, 1998, which claims the benefit of the filing date of U.S. provisionalpatent application No. 60/038,908, filed Feb. 26, 1997.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY-SPONSOREDRESEARCH AND DEVELOPMENT

This invention was made with U.S. Government support under grant nos.CA-35711, AA-00026 and AA-002169, awarded by the National Institutes ofHealth. The U.S. Government has certain rights in this invention.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is in the field of genetic engineering andmolecular biology. In particular, the invention is directed totransgenic animals and transfected cell lines expressing a proteinassociated with Alzheimer's Disease, neuroectodermal tumors, malignantastrocytomas, and glioblastomas. This invention is also directed to theuse of such transgenic animals and transfected cell lines to screenpotential drug candidates for treating or preventing Alzheimer'sdisease. The invention also relates to new antisense oligonucleotides,ribozymes, triplex forming DNA and external guide sequences that can beused to treat or prevent Alzheimer's disease.

2. Related Art

Alzheimer's disease (AD) (Khachaturian, Z. S., “Diagnosis of Alzheimer'sDisease,” Arch. Neurol. 421:1097-1105 (1985)) is the most prevalentneurodegenerative disease and the most common cause of dementia in theWestern hemisphere. AD neurodegeneration is characterized by prominentatrophy of corticolimbic structures with neuronal loss, neurofibrillarytangle formation, aberrant proliferation of neurites, senile plaques,and βA4-amyloid deposition in the brain (Khachaturian, Z. S.).Approximately 90 percent of AD occurs sporadically. The cause isunknown, but the most important overall risk factor is aging (Takman,A., “Epidemiology of Alzheimer's Disease. Issues of Etiology andValidity,” Acta Neurol. Scand. Suppl. 145:1-70 (1993)). Theapolipoprotein ε4 genotype (Corder, E. H. et al., “Gene Does ofApolipoprotein E Type 4 Allele and the Risk of Alzheimer's Disease inLate Onset Families, Science 261:921-923 (1993)) and a family history ofTrisomy 21 Down syndrome (Lai, F. and Williams, R. S., “A ProspectiveStudy of Alzheimer Disease in Down Syndrome,” Arch. Neurol. 46:849-853(1989) increase risk or accelerate the course of sporadic AD. Familialforms of AD, which account for 5 to 10 percent of the cases, have beenlinked to mutations in the amyloid precursor protein (APP) gene(Kennedy, A. M. et al., “Familial Alzheimer's Disease. A Pedigree With aMis-Sense Mutation in the Amyloid Precursor Protein Gene (AmyloidPrecursor Protein 717 Valine-->Glycine,” Brain 309-324(1993); Peacock,M. L. et al., “Novel Amyloid Precursor Protein Gene Mutation (Codon 665Asp) in a Patient with Late-Onset Alzheimer's Disease,” Ann. Neurol.35:432-438 (1994); Tanzi, R. E. et al., “Assessment of AmyloidBeta-Protein Precursor Gene Mutations in a Large Set of Familial andSporadic Alzheimer's Disease Cases,” Am. J. Hum. Genet. 51:273-282(1992)) located on Chromosome 21 (Robakis, N. K. et al., Chromosome21q21 Sublocalization of Gene Encoding Beta-Amyloid Peptide in CerebralVessels and Neuritic (Senile) Plaques of People with Alzheimer Diseaseand Down Syndrome,” Lancet 1:384-385 (1987)), or presenilin geneslocated on Chromosomes 1 and 14 (Levy-Lahad, E. et al., “Candidate Genefor the Chromosome 1 Familial Alzheimer's Disease Locus,” Science18:973-977 (1995); Sorbi, S. et al., “Missense Mutation of S182 Gene inItalian Families With Early Onset Alzheimer's Disease,” Lancet346:439-440 (1995); Sherrington, R. et al., “Cloning of a Gene BearingMissense Mutations in Early-Onset Familial Alzheimer's Disease, Nature375:754-760 (1995); Rogaev, E. I. et al., “Familial Alzheimer's Diseasein Kindreds With Missense Mutations in a Gene on Chromosome 1 Related tothe Alzheimer's Disease Type 3 Gene,” Nature 376:775-778 (1995);Barinaga, M. et al., “Candidate Gene for the Chromosome 1 FamilialAlzheimer's Disease Locus,” Science 269:973-977 (1995)). Over-expressionand abnormal cleavage of APP may promote AD neurodegeneration since allindividuals with Trisomy 21 Down syndrome who survive beyond the fourthdecade develop AD with extensive central nervous system (CNS)accumulations of βA4-amyloid (Lai, F. and Williams, R. S., “AProspective Study of Alzheimer Disease in Down Syndrome,” Arch. Neurol.46:849-853 (1989)), and experimentally, βA4-amyloid is neurotoxic andapotogenic (LaFerla, F. M. et al., “The Alzheimer's A Beta PeptideInduces Neurodegeneration and Apoptotic Cell Death in Transgenic Mice,”Nat. Genet. 9:21-30 (1995). In addition, missense mutations inpersenilin 1, as occurs in nature, cause vasculopathy and massiveaccumulations of peptides in the brain (Lemere, C. A. et al., “The E280APresenilin 1 Alzheimer Mutation Produces Increased Aβ42 Deposition andSevere Cerebellar Pathology,” Nature Med. 2:1146-1150 (1996); Mann, D.M. et al., “Amyloid Beta Protein (Abeta) Deposition in Chromosome14-Linked Alzheimer's Disease: Predominance of Abeta42(43),” Ann Neurol.40:149-156 (1996)).

Central nervous system biochemical and molecular abnormalitiesidentified in AD include: 1) increased phosphorylation of tau and othercytoskeletal proteins in neurons (Grundke-Iqbal, I. et al., “AbnormalPhosphorylation of the Microtubule-Associated Protein τ (tau) inAlzheimer Cytoskeletal Pathology,” Proc. Natl. Acad. Sci. U.S.A.83:4913-4917 (1986)); 2) aberrant expression of genes modulated withneuritic sprouting such as the growth associated protein, GAP-43 (de laMonte, S. M. et al., “Aberrant GAP-43 Gene Expression in Alzheimer'sDisease,” Am. J. Pathol. 147:934-946 (1995)), constitutive endothelialnitric oxide synthase (de la Monte, S. M. and Bloch, K. D. “AberrantExpression of the Constitutive Endothelial Nitric Oxide Synthase Gene inAlzheimer's Disease,” Molecular and Chemical Neuropathy 29: (in press))transforming growth factor β (Peress, N. S. and Perillo, E.,“Differential Expression of TGF-beta 1, 2, and 3 Isotypes in Alzheimer'sDisease: a Comparative Immunohistochemical Study With CerebralInfarction, Aged Human and Mouse Control Brains,” J. Neuropathol. Exp.Neurol. 54: 802-811 (1995)), and metallothionine-3 (Aschner, M. “TheFunctional Significance of Brain Metallothioneins,” Faseb. J.10:1129-1136 (1996)); 3) increased expression of genes associated withglial cell activation, such as glial fibrillary acidic protein(Goodison, K. L. et al., “Neuronal and Glial Gene Expression inNeocortex of Down's Syndrome,” J. Neuropathol. Exp. Neurol. 52:192-198(1993)) and alpha-1 antichymotrypsin (Pastemack, J. M. et al.,“Astrocytes in Alzheimer's Disease Gray Matter Express Alpha1-Antichymotrypsin mRNA,” Am. J. Path. 135:827-834 (1989); and 4)altered expression of genes that protect neurons from either cytotoxicor programmed cell death, including sulfated glycoprotein-2 (May, P. C.et al., “Dynamics of Gene Expression for a Hippocampal GlycoproteinElevated in Alzheimer's Disease and in Response to Experimental Lesionsin Rat,” Neuron 5:831-839 (1990), cathepsin D (Cataldo, A. M. et al.,“Gene Expression and Cellular Content of Cathepsin D in Alzheimer'sDisease Brain: Evidence for Early Up-Regulation of theEndosomal-Lysosomal System,” Neuron 14:671-680 (1995)), superoxidedismutase 1 (Somerville, M. J. et al., “Localization and Quantitation of68 kDA Neurofilament and Superoxide Dismutase-1 mRNA in AlzheimerBrains, Brain Res. Mol. Brain Res. 9:1-8 (1991), mitochondrialcytochrome oxidase (Chandrasekaran, K. et al., “Impairment inMitochondrial Cytochrome Oxidase Gene Expression In Alzheimer Disease,”Brain Res. Mol. Brain. Res. 24:336-340 (1994)), C1q component ofcomplement (Fischer, B. et al., “Complement C1q and C3 mRNA Expressionin the Frontal Cortex of Alzheimer's Patients,” J. Mol. Med. 73:465-471(1995)), Calbindin D28k (Yamagishi, M. et al., “Ontogenetic Expressionof Spot 35 Protein (Calbindin-D28k) in Human Olfactory Receptor Neuronsand its Decrease in Alzheimer's Disease Patients,” Ann. Ontol. Rhinol.Laryngol. 105:132-139 (1996), and bcl-2 (O'Barr, S. et al., “Expressionof the Protooncogene bcl-2 in Alzheimer's Disease Brain,” Neurobiol.Aging 17:131-136 (1996).

In previous studies, we demonstrated increased immunoreactivity in ADbrains using a polyclonal antisera prepared against a pancreatic protein(Ozturk, M. et al., “Elevated Levels of an Exocrine Pancreatic SecretoryProtein in Alzheimer's Disease Brain,” Proc. Natl. Acad. Sci. U.S.A.86:419-423 (1989); de la Monte, S. M. et al., “Enhanced Expression of anExocrine Pancreatic Protein in Alzheimer's Disease and the DevelopingHuman Brain,” J. Clin. Invest. 86:1004-1013 (1990); WO90/06993). Usingsuch polyclonal antibodies, we isolated the AD7c-NTP cDNA from an ADbrain expression library (WO94/23756). In WO94/23756, this clone is alsoreferred to as AD10-7, which was deposited in DH1 cells at the ATCCunder accession no. 69262. The nucleotide sequence of this cDNA is shownin FIG. 16R of WO94/23756. However, this sequence comprises numerouserrors. See also WO96/15272 (Seq. ID No. 120, pages 168-170), which alsocomprises numerous errors. As a result, the predicted amino acidsequence (Seq. ID No. 121; WO96/15272) is also wrong.

SUMMARY OF THE INVENTION

The present invention is related to transgenic animals and cell lineswhich over express the AD7c-NTP and use thereof to screen candidatedrugs for use in the treatment or prevention of Alzheimer's disease,neuroectodermal tumors, malignant astrocytomas and glioblastomas.

In particular, the invention relates to a DNA construct, wherein saidDNA construct comprises a DNA molecule having Seq. ID No. 1 or a DNAsequence at least 40% homologous thereto, or a fragment thereof.Preferably, the DNA molecule is under control of a heterologous,neuro-specific promoter.

The invention also relates to cell lines containing the DNA construct ofthe invention.

The invention also relates to transgenic non-human animals whichcomprise the DNA construct of the invention. Preferably, the transgenicanimals over-express AD7c-NTP.

The invention also relates to an in vitro method for screening candidatedrugs that are potentially useful for the treatment or prevention ofAlzheimer's disease, neuroectodermal tumors, malignant astrocytomas, andglioblastomas, which comprises

-   -   (a) contacting a candidate drug with a host transfected with a        DNA construct, wherein the DNA construct comprises a DNA        molecule of Seq. ID No. 1 or a DNA molecule at least 40%        homologous thereto, or a fragment thereof, and wherein said host        over expresses the protein coded for by said DNA molecule, and    -   (b) detecting at least one of the following:        -   (i) the suppression or prevention of expression of the            protein;        -   (ii) the increased degradation of the protein; or        -   (iii) the reduction of frequency of at least one of neuritic            sprouting, nerve cell death, degenerating neurons,            neurofibrillary tangles, or irregular swollen neurites and            axons in the host;            due to the drug candidate compared to a control host that            has not received the candidate drug.

In a preferred embodiment, the host is a transgenic animal. In anotherpreferred embodiment, the host is a cell in vitro.

The invention is also directed to antisense oligonucleotides which arecomplementary to an NTP nucleic acid sequence and which is nonhomologousto PTP nucleic acid sequences and that correspond to regions that wereincorrectly sequenced in the past, as well as pharmaceuticalcompositions comprising such oligonucleotides and a pharmaceuticallyacceptable carrier.

The invention is also directed to ribozymes comprising a target sequencewhich is complementary to an NTP sequence and nonhomologous to PTPnucleic acid sequences and that correspond to regions that wereincorrectly sequenced in the past, as well as pharmaceuticalcompositions comprising such ribozymes and a pharmaceutically acceptablecarrier.

The invention is also directed to oligodeoxynucleotides that form triplestranded regions with the AD7c-NTP gene, which are nonhomologous to PTPnucleic acid sequences, and that correspond to regions that wereincorrectly sequenced in the past, as well as pharmaceuticalcompositions comprising such oligodeoxynucleotides and apharmaceutically acceptable carrier.

The invention is also directed to a method of achieving pharmaceuticaldelivery of the antisense oligonucleotides, ribozymes and triple helixoligonucleotides to the brain through acceptable carriers or expressionvectors.

The invention is also directed to the therapeutic use of the antisenseoligonucleotides, ribozymes and triple helix oligonucleotides to modifyor improve dementias of the Alzheimer's type of neuronal degeneration;as well as to treat or prevent neuroectodermal tumors, malignantastrocytomas, and glioblastomas.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A-1C depict the nucleotide and translated amino acid sequence(Seq ID Nos. 1 and 2) of the AD7c-NTP cDNA. The shaded regioncorresponds to the nucleic acid sequences detected in 6 AD brains byRT-PCR analysis of mRNA. The cDNA exhibits significant homology with Alugene, and to an unknown gene in the Huntington region, Chromosome 4q16.3(underlined). The open reading frame begins with the first methioninecodon. The translated amino acid sequence encodes a 41.3 kD protein witha hydrophobic leader sequence (italics) followed by a myristoylationmotif (bold, italics) and potential AI cleavage site. That same region(italics, underlined) exhibits significant homology with theinsulin/IGF-1 chimeric receptor. There are 17 potential glycogensynthase kinase-3, protein kinase C, or cAMP or Ca-dependent kinase IIphosphorylation motifs and one transforming growth factor (tgf) motif(double underlined). The embolded amino acid sequences exhibitsignificant homology with the A4 alternatively spliced mutant form ofNF2, β subunit of integrin, and human decay accelerating factor 2precursor. The boxed amino acid sequences exhibit significant homologywith human integral membrane protein and myclin oligoglycoprotein-16.

FIGS. 2A-2F depict AD7c-NTP expression in vitro and in vivo. (2A):Recombinant protein detected by in vitro translation using sense strandcRNA transcripts. (2B): Western blot analysis of purified recombinantprotein demonstrating specific immunoreactivity with the Tag and N3I4AD7c-NTP monoclonal antibodies, but not with non-relevant FB50monoclonal antibody. (2C): Western blot analysis of BOSC cells stablytransfected with pcDNA3-AD7c-NTP or pcDNA3 (empty vector). The blotswere probed with the N3I4 AD7c-NTP antibody. (2D): Significantlyincreased levels of the 41-45 kD AD7c-NTP protein in AD frontal loberelative to age-matched control frontal lobe tissue. Similar resultswere obtained for temporal lobe tissue. (2E): Higher levels of the 41-45kD and 19-21 kD AD7c-NTP proteins in late, end-stage (L) AD comparedwith early, less symptomatic (E) AD. All tissue samples were taken fromthe frontal lobe. Note the clusters of 3 or 4 bands between ˜41 and ˜45kD, probably corresponding to different degrees of phosphorylation.(2F): Western blot analysis of postmortem ventricular fluiddemonstrating higher levels of the ˜41 kD AD7c-NTP molecules in ADcompared with aged control samples using the N3I4 antibody. The ˜28-30kD band may represent a degradation product. Also note detection of the˜19-21 kD N3I4-immunoreactive molecules in AD.

FIGS. 3A-3F depict AD7c-NTP mRNA expression in AD and aged controlbrains. Northern blot analysis of AD and aged control frontal lobe RNAdetected ˜1.4 kB transcripts corresponding to the size of the AD&c-NTPcDNA. In addition, ˜0.9 kB transcripts corresponding to a different cDNAwere detected in all brains, but not in other tissues. Densitometricanalysis of the autoradiograms revealed variable levels of AD7c-NTP mRNAexpression in the AD group (3A), but significantly higher mean levels ofthe 1.4 kB AD7c-NTP transcript in the AD (N=17) relative to the agedcontrol (N=11) group (P<0.01). (FIGS. 3C and 3D): Brightfieldphotomicrographs of in situ hybridization results using antisense (3C)or sense (3D; negative control) digoxigenin-labeled cRNA probes. Arrowsindicate examples of neurons and dark grains represent positivehybridization signals. (FIGS. 3E and 3F): Darkfield photomicrographs ofin situ hybridization results demonstrating more intense labeling (whitegrains) in AD (3E) relative to aged control (3F) cortical neurons(arrows) in the frontal lobe. Probe labeling was detected withantidigoxigenin and alkaline phosphatase substrates (see below). Thewhite signals aggregated over neurons (pyramidal shaped) representpositive results, and black areas indicate absent probe binding.

FIGS. 4A-4H depict increased AD7c-NTP immunoreactivity in AD (4A)relative to aged control (4B) cortical neurons by immunohistochemicalstaining with the N2T8 (4A and 4B). N2J1 immunoreactivity in AD brains(FIGS. 4C, 4E-4H) demonstrating high-level AD7c-NTP expression oraccumulation in the perikarya of cytologically intact (4C) as well asdegenerating (4E) neurons. In addition, the N2J1 antibody wasimmunoreactive with abnormal dystrophic cell processes occurring inaggregates (sprouts) (4F), dispersed in the white matter (4G), andcorresponding to irregular beaded axons (4H). FIG. 4D depicts ADcerebral cortex immunostained with non-relevant antibody. The sectionsin FIGS. 4A and 4B were counter stained with hematoxylin to provide acontrasting background.

FIGS. 5A and 5B depict graphs showing increased cell death inpcDNA3-AD7c-NTP transfected SH-Sy5y cells. Synchronized cells were fedwith medium containing 10% fetal calf serum, and DNA synthesis wasassessed by ³H-thymidine incorporation into DNA (5A). The density ofviable cells was determined at each time point (5A). Despite higherlevels of DNA synthesis (5B), cell density was significantly reduced in4 replicate AD7c-NTP-transfected cultures compared with control(pcDNA3-transfected) cells. AD7c-NTP-transfected cells also exhibitedincreased nuclear p53 immunoreactivity and increased nuclear DNAfragmentation by the in situ assay for nicked DNA (TUNEL), suggestingthat over-expression of AD7c-NTP in neuronal cells causes apoptosis.

FIGS. 6A-6G show that AD7c-NTP over-expression in transfected neuronalcells results in increased neuritic sprouting. (6A): SH-Sy5y cellsstably transfected with pcDNA3 (empty vector). (6B-6D): SH-Sy5y cellsstably transfected with pcDNA3-AD7c-NTP. Note fine neuritic processes(arrows) on most cells in FIGS. 6B-6D. Also note lower cell density andnumerous round refractile dead cells (arrowheads) in FIG. 6D comparedwith FIG. 6A. (FIG. 6E-6G): Immunocytochemical staining of SH-Sy5y cellsstably transfected with pcDNA3 (6E) or pcDNA3-AD7c-NTP (6F, 6G) usingN3I4 monoclonal antibody. Note intense labeling of perikarya and cellprocesses (arrows) in 6F and 6G and absent labeling in 6E.

FIGS. 7A-7C depict modulation of gene expression following IPTGinduction of AD7c-NTP expression. LacA-control cells (FIG. 7A) lackAD7c-NTP; LacB-B6 cells (FIG. 7B) and LacF-B6 cells (FIG. 7C) are twodifferent clones with different levels of AD7c-NTP induction. Changes inthe level of expression 24 hours after induction are indicated for genesinvolved in AD, neural sprouting, and apoptosis.

FIGS. 8A-8D depict IPTG dose-dependent increases in the level of the NTP(FIG. A), Tau (FIG. B), Synaptophysin (FIG. C) and p53 (FIG. D)proteins. The percent change of the amount of each protein is presentedas a function of IPTG concentration (mM).

FIGS. 9A and 9B depict the effects of AD7c-NTP expression in CYZneuronal cells on metabolic (MTT) activity and cell viability. Lac A-LacF represent six different clones, and B6 indicates AD7c-NTP expression.The percent change for MTT activity (FIG. 9A) and cell viability (FIG.9B) are indicated for control (Lac A-Control) and AD7c-NTP expressingcell lines.

FIGS. 10A and 10B depict the effect of AD7c-NTP expression on cellviability. Nonexpressing Lac A Control and cell lines expressingAD7c-NTP at various levels, Lac B-B6 and Lac F-B6, were assayed forviability after varying exposure time to the protein expression inducingagent (IPTG) and various oxidative stress toxins.

FIG. 11 depicts DNA fragmentation after IPTG induction of AD7c-NTPexpression, thereby providing a quantitative assessment of apoptosis.Stably transfected CYZ neuronal cell lines, Lac A, Lac B and Lac F,which express various levels of AD7c-NTP after induction, were incubatedin the presence of ³²dCTP label. The amount of radioactive isotopeincorporated, under control (uninduced) and IPTG induction conditions,into the respective cell line DNAs is presented.

FIG. 12 depicts the percent change in viability for cells stablytransfected with and expressing AD7c-NTP under conditions that promoteand reduce or block oxidative stress. Agents promoting oxidative stressare the following: hydrogen peroxide (H₂O₂) diethyldithiocarbamic acid(DDC), S-nitro-N-acetyl-penicillamine (SNAP) and N-acetyl cysteine; andthe agent utilized to block or reduce oxidative stress is pygroglutamate(PG).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Definitions

In the description that follows, a number of terms used in recombinantDNA technology are utilized extensively. In order to provide a clear andconsistent understanding of the specification and claims, including thescope to be given such terms, the following definitions are provided.

Cloning vector. A plasmid or phage DNA or other DNA sequence which isable to replicate autonomously in a host cell, and which ischaracterized by one or a small number of restriction endonucleaserecognition sites at which such DNA sequences may be cut in adeterminable fashion without loss of an essential biological function ofthe vector, and into which a DNA fragment may be spliced in order tobring about its replication and cloning. The cloning vector may furthercontain a marker suitable for use in the identification of cellstransformed with the cloning vector. Markers, for example, providetetracycline resistance or ampicillin resistance.

Expression vector. A vector similar to a cloning vector but which iscapable of enhancing the expression of a gene which has been cloned intoit, after transformation into a host. The cloned gene is usually placedunder the control of (i.e., operably linked to) certain controlsequences such as promoter sequences. Promoter sequences may be eitherconstitutive or inducible.

Substantially pure. As used herein means that the desired purifiedprotein is essentially free from contaminating cellular components, saidcomponents being associated with the desired protein in nature, asevidenced by a single band following polyacrylamide-sodium dodecylsulfate gel electrophoresis. Contaminating cellular components mayinclude, but are not limited to, proteinaceous, carbohydrate, or lipidimpurities.

The term “substantially pure” is further meant to describe a moleculewhich is homogeneous by one or more purity or homogeneitycharacteristics used by those of skill in the art. For example, asubstantially pure NTP will show constant and reproduciblecharacteristics within standard experimental deviations for parameterssuch as the following: molecular weight, chromatographic migration,amino acid composition, amino acid sequence, blocked or unblockedN-terminus, HPLC elution profile, biological activity, and other suchparameters. The term, however, is not meant to exclude artificial orsynthetic mixtures of the factor with other compounds. In addition, theterm is not meant to exclude NTP fusion proteins isolated from arecombinant host.

Recombinant Host. According to the invention, a recombinant host may beany prokaryotic or eukaryotic host cell which contains the desiredcloned genes on an expression vector or cloning vector. This term isalso meant to include those prokaryotic or eukaryotic cells that havebeen genetically engineered to contain the desired gene(s) in thechromosome or genome of that organism. For examples of such hosts, seeSambrook et al., Molecular Cloning: A Laboratory Manual, Second Edition,Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y. (1989).Preferred recombinant hosts are neuronal cells transformed with the DNAconstruct of the invention. Such neuronal cells include brain cells thathave been isolated after mechanical disassociation of an animal brain orother available neuronal cell lines.

Recombinant vector. Any cloning vector or expression vector whichcontains the desired cloned gene(s).

Host Animal. Transgenic animals, all of whose germ and somatic cellscontain the DNA construct of the invention. Such transgenic animals arein general vertebrates. Preferred Host Animals are mammals such asnon-human primates, mice, sheep, pigs, cattle, goats, guinea pigs,rodents, e.g. rats, and the like. The term Host Animal also includesanimals in all stages of development, including embryonic and fetalstages.

Promoter. A DNA sequence generally described as the 5′ region of a gene,located proximal to the start codon. The transcription of an adjacentgene(s) is initiated at the promoter region. If a promoter is aninducible promoter, then the rate of transcription increases in responseto an inducing agent. In contrast, the rate of transcription is notregulated by an inducing agent if the promoter is a constitutivepromoter. According to the invention, preferred promoters areheterologous to the AD7c-NTP gene, that is, the promoters do not driveexpression of the gene in a human. Such promoters include the CMVpromoter (InVitrogen, San Diego, Calif.), the SV40, MMTV, and hMTIIapromoters (U.S. Pat. No. 5,457,034), the HSV-1 4/5 promoter (U.S. Pat.No. 5,501,979), and the early intermediate HCMV promoter (WO92/17581).Also, it is preferred that the promoter is neuro-specific, that is, itis induced selectively in neuronal tissue. Also, neuro-specific enhancerelements may be employed. Examples of neuro-specific promoters includebut are not limited to the promoter which controls the neurofilamentgene (WO91/02788; Byrne and Ruddle, Proc. Natl. Acad. Sci. USA86:5473-5477 (1989)), the neuron specific promoter of the humanneurofilament light gene (NFL) (U.S. Pat. No. 5,569,827); the promoterof the β2-subunit of the neuronal nicotinic acetylcholine receptor (EP 0171 105; U.S. application Ser. No. 08/358,627), the hThy-1 promoter(WO95/03397; U.S. application Ser. No. 08/096,944; Gordon, J. et al.,Cell 50:445-452 (1987)); the Tα1 α-tubulin promoter (WO95/25795; U.S.application Ser. No. 08/215,083; Gloster et al., J. Neurosci.14:7319-7330 (1994)), the APP promoter, the rat neuron specificpromoter, the human β actin gene promoter, the human platelet derivedgrowth factor B (PDGF-B) chain gene promoter, the rat sodium channelgene promoter, the mouse myelin basic protein gene promoter, the humancopper-zinc superoxide dismutase gene promoter, mammalian POU-domainregulatory gene promoter (WO93/14200; U.S. application Ser. Nos.07/817,584 and 07/915,469); human platelet derived growth factor B(PDGF-B) chain gene promoter (WO96/40895; U.S. application Ser. Nos.08/486,018 and 08/486,538; Sasahara et al., Cell 64:217-227 (1991)); andthe neuron-specific enolase promoter (McConlogue et al., Aging 15:S12(1994); Higgins et al., Ann Neurol. 35:598-607 (1995); Mucke et al.,Brain Res. 666:151-167 (1994); Higgins et al., Proc. Natl. Acad. Sci USA92:4402-4406 (1995); WO96/40896; U.S. application Ser. No. 08/480,653;and U.S. Pat. No. 5,387,742); and sequences that regulate theoligodendroglial-specific expression of JC virus, glial-specificexpression of the proteolipid protein, and the glial fibrillary acidicprotein genes (U.S. Pat. No. 5,082,670). Other neuro-specific promoterswill be readily apparent to those of skill in the art. Since proteinphosphorylation is critical for neuronal regulation (Kennedy, “SecondMessengers and Neuronal Function,” in An Introduction to MolecularNeurobiology, Hall, Ed., Sinauer Associates, Inc. (1992)), proteinkinase promoter sequences can be used to achieve sufficient levels ofNTP gene expression.

Gene. A DNA sequence that contains information needed for expressing apolypeptide or protein.

Structural gene. A DNA sequence that is transcribed into messenger RNA(mRNA) that is then translated into a sequence of amino acidscharacteristic of a specific polypeptide.

Antisense RNA gene/Antisense RNA. In eukaryotes, mRNA is transcribed byRNA polymerase II. However, it is also known that one may construct agene containing a RNA polymerase II template wherein a RNA sequence istranscribed which has a sequence complementary to that of a specificmRNA but is not normally translated. Such a gene construct is hereintermed an “antisense RNA gene” and such a RNA transcript is termed an“antisense RNA.” Antisense RNAs are not normally translatable due to thepresence of translation stop codons in the antisense RNA sequence.

Antisense oligonucleotide. A DNA or RNA molecule or a derivative of aDNA or RNA molecule containing a nucleotide sequence which iscomplementary to that of a specific mRNA. An antisense oligonucleotidebinds to the complementary sequence in a specific mRNA and inhibitstranslation of the mRNA. There are many known derivatives of such DNAand RNA molecules. See, for example, U.S. Pat. Nos. 5,602,240,5,596,091, 5,506,212, 5,521,302, 5,541,307, 5,510,476, 5,514,787,5,543,507, 5,512,438, 5,510,239, 5,514,577, 5,519,134, 5,554,746,5,276,019, 5,286,717, 5,264,423, as well as WO96/35706, WO96/32474,WO96/29337 (thiono triester modified antisense oligodeoxynucleotidephosphorothioates), WO94/17093 (oligonucleotide alkylphosphonates andalkylphosphothioates), WO94/08004 (oligonucleotide phosphothioates,methyl phosphates, phosphoramidates, dithioates, bridgedphosphorothioates, bridge phosphoramidates, sulfones, sulfates, ketos,phosphate esters and phosphorobutylamines (van der Krol et al., Biotech.6:958-976 (1988); Uhlmann et al., Chem. Rev. 90:542-585 (1990)),WO94/02499 (oligonucleotide alkylphosphonothioates andarylphosphonothioates), and WO92/20697 (3′-end capped oligonucleotides).Particular NTP antisense oligonucleotides of the present inventioninclude derivatives such as S-oligonucleotides (phosphorothioatederivatives or S-oligos, see, Jack Cohen, Oligodeoxynucleotides,Antisense Inhibitors of Gene Expression, CRC Press (1989)). S-oligos(nucleoside phosphorothioates) are isoelectronic analogs of anoligonucleotide (O-oligo) in which a nonbridging oxygen atom of thephosphate group is replaced by a sulfur atom. The S-oligos of thepresent invention may be prepared by treatment of the correspondingO-oligos with 3H-1,2-benzodithiol-3-one-1,1-dioxide which is a sulfurtransfer reagent. See Iyer et al., J. Org. Chem. 55:4693-4698 (1990);and Iyer et al., J. Am. Chem. Soc. 112:1253-1254 (1990).

Antisense Therapy. A method of treatment wherein antisenseoligonucleotides are administered to a patient in order to inhibit theexpression of the corresponding protein.

Complementary DNA (cDNA). A “complementary DNA,” or “cDNA” gene includesrecombinant genes synthesized by reverse transcription of mRNA and fromwhich intervening sequences (introns) have been removed.

Expression. Expression is the process by which a polypeptide is producedfrom a structural gene. The process involves transcription of the geneinto mRNA and the translation of such mRNA into polypeptide(s).

Homologous/Nonhomologous Two nucleic acid molecules are considered to be“homologous” if their nucleotide sequences share a similarity of greaterthan 40%, as determined by HASH-coding algorithms (Wilber, W. J. andLipman, D. J., Proc. Natl. Acad. Sci. 80:726-730 (1983)). Two nucleicacid molecules are considered to be “nonhomologous” if their nucleotidesequences share a similarity of less than 40%.

Ribozyme. A ribozyme is an RNA molecule that contains a catalyticcenter. The term includes RNA enzymes, self-splicing RNAs, andself-cleaving RNAs.

Ribozyme Therapy. A method of treatment wherein ribozyme is administeredto a patient in order to inhibit the translation of the target mRNA.

Fragment. A “fragment” of a molecule such as NTP is meant to refer toany polypeptide subset of that molecule.

Functional Derivative. The term “functional derivatives” is intended toinclude the “variants,” “analogues,” or “chemical derivatives” of themolecule. A “variant” of a molecule such as NTP is meant to refer to anaturally occurring molecule substantially similar to either the entiremolecule, or a fragment thereof. An “analogue” of a molecule such as NTPis meant to refer to a non-natural molecule substantially similar toeither the entire molecule or a fragment thereof.

A molecule is said to be “substantially similar” to another molecule ifthe sequence of amino acids in both molecules is substantially the same,and if both molecules possess a similar biological activity. Thus,provided that two molecules possess a similar activity, they areconsidered variants as that term is used herein even if one of themolecules contains additional amino acid residues not found in theother, or if the sequence of amino acid residues is not identical.

As used herein, a molecule is said to be a “chemical derivative” ofanother molecule when it contains additional chemical moieties notnormally a part of the molecule. Such moieties may improve themolecule's solubility, absorption, biological half-life, etc. Themoieties may alternatively decrease the toxicity of the molecule,eliminate or attenuate any undesirable side effect of the molecule, etc.Examples of moieties capable of mediating such effects are disclosed inRemington's Pharmaceutical Sciences (1980) and will be apparent to thoseof ordinary skill in the art.

AD7c-NTP. The term “AD7c-NTP” refers to the protein having sequence IDNo. 2 as well as allelic variants thereof.

We have isolated a cDNA designated AD7c-NTP, that is expressed inneurons, and over-expressed in brains with AD. The 1442-nucleotideAD7c-NTP cDNA encodes a ˜41 kD membrane spanning protein that has ahydrophobic leader sequence and myristylation motif near the aminoterminus. The AD7c-NTP cDNA is an Alu sequence-containing gene withthree regions of significant homology to the alternatively spliced A4form of NF2, the β1 subunit of integrin, human integral membraneprotein, myelin oligoglycoprotein-16 precursor, and human decayaccelerating factor 2 precursor, and two regions with significanthomology with sequences in the Huntington's disease region on Chromosome4p16.3. Expression of AD7c-NTP was confirmed by nucleic acid sequencingof RT-PCR products isolated from brain. AD7c-NTP cRNA probes hybridizedwith 1.4 kB and 0.9 kB mRNA transcripts by Northern blot analysis, andmonoclonal antibodies generated with the recombinant protein wereimmunoreactive with ˜39-45 kD and ˜19-21 kD molecules by Western blotanalysis of human brain. Quantitation of data obtained from 17 AD and 11age-matched control brains demonstrated significantly higher levels ofAD7c-NTP expression in AD. In situ hybridization and immunostainingstudies localized AD7c-NTP gene expression in neurons, and confirmed theover-expression associated with AD neurodegeneration. Increased AD7c-NTPprotein levels were also detectable in cerebrospinal fluid by Westernblot analysis. The results suggest that abnormal AD7c-NTP geneexpression is associated with AD neurodegeneration. Thus, abnormalexpression of AD7c-NTP is a phenotype associated with Alzheimer'sdisease.

The confirmation that AD7c-NTP expression leads to Alzheimer's diseaseled to the expectation that transgenic animals and cell lines which overexpress the AD7c-NTP can be used to screen drugs for use in thetreatment or prevention of Alzheimer's disease, neuroectodermal tumors,malignant astrocytomas and glioblastomas.

The invention relates to a DNA construct, wherein said DNA constructcomprises a DNA molecule of Seq. ID No. 1, or a fragment thereof, or aDNA molecule which is at least 40% homologous thereto, more preferably,at least 85% homologous thereto, most preferably, at least 90%homologous thereto. Preferably, the DNA construct encodes AD7c-NTPhaving Seq. ID NO. 2. Also preferably, the DNA sequence is under controlof a heterologous neuro-specific promoter. Examples of promoters thatcan be used to drive expression of AD7c-NTP in a host cell are describedabove. Having the promoter in hand, one may simply ligate the promoterto the DNA molecule of Seq. ID No. 1. Methods for ligating DNA fragmentsare well known to those of ordinary skill in the art. Preferably, theDNA molecule having Seq. ID No. 1 is ligated to a plasmid which containsthe promoter and which results in the promoter being in operable linkageto the AD7c-NTP DNA sequence.

Fragments of the DNA molecule of the invention code for proteins havingthe activity of AD7c-NTP, that is, the DNA fragments induce neutiticsprouting, nerve cell death, nerve cell degeneration, neurofibrillarytangles, and/or irregular swollen neurites in a host which expresses thefragment. Such hosts include cellular hosts and transgenic animals.

DNA molecules which are at least 40%, 85% or 90% homologous to Seq. IDNo. 1 may be isolated from cDNA libraries of humans and animals byhybridization under stringent conditions to the DNA molecule of Seq. IDNo. 1 according to methods known to those of skill in the art. Stringenthybridization conditions are employed which select for DNA moleculeshaving at least 40%, 85% and 90% homology to Seq. ID No. 1 are describedin Sambrook et al., In: Molecular Cloning, A Laboratory Manual, ColdSpring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (1989); andManiatis et al., Molecular Cloning—A Laboratory Manual, Cold SpringHarbor Laboratory, Cold Spring Harbor, N.Y., 1985. The hybridizationsmay be carried out in 6×SSC/5×Denhardt's solution/0.1% SDS at 65° C. Thedegree of stringency is determined in the washing step. Thus, suitableconditions include 0.2×SSC/0.01% SDS/65° C. and 0.1×SSC/0.01% SDS/65° C.

The invention also relates to cells containing the DNA construct of theinvention. Examples of suitable cells that may contain the DNA constructof the invention include eukaryotic and prokaryotic cells. Preferred areeukaryotic cells such as those derived from a vertebrate animalincluding human cells, non-human primate cells, porcine cells, ovinecells and the like. Further, it is contemplated that the cell line maybe a neuronal cell line from one of these vertebrate animals. Examplesof such cell lines include SH-Sy5y, pNET-1, pNET-2, hNTs (Stratagene,Inc.), and A172 (ATCC) neuronal cells. See O'Barr, S. et al., Neurobiol.Aging 17:131-136 (1996); Ozturk, M. et al., Proc. Natl. Acad. Sci. USA86:419-423 (1989); Bieldler, et al., Cancer Res. 33:2643-2652 (1973);and The et al., Nature Genet. 3:2643-2652 (1993).

Methods for introducing DNA constructs into cells in vitro, in vivo andex vivo are well known to those of ordinary skill in the art. See, forexample, U.S. Pat. Nos. 5,595,899, 5,521,291, 5,166,320, 5,547,932,5,354,844, 5,399,346, WO94/10569 and Citron et al., Nature 360:622-674(1995).

The invention also relates to transgenic non-human animals whichcomprise the DNA construct of the invention in each of its germ andsomatic cells and which over express AD7c-NTP. Such transgenic animalsmay be obtained, for example, by injecting the DNA construct of theinvention into a fertilized egg which is allowed to develop into anadult animal. To prepare a transgenic animal, a few hundred DNAmolecules are injected into the pro-nucleus of a fertilized one cellegg. The micro injected eggs are then transferred into the oviducts ofpseudopregnant foster mothers and allowed to develop. It has beenreported by Brinster et al., Proc. Natl. Acad. Sci. USA 82:4438-4442(1985), that about 25% of mice which develop will inherit one or morecopies of the micro injected DNA. Alternatively, the transgenic animalsmay be obtained by utilizing recombinant ES cells for the generation ofthe transgenes, as described by Gossler et al., Proc. Natl. Acad. Sci.USA 83:9065-9069 (1986). The offspring may be analyzed for theintegration of the transgene by isolating genomic DNA from tail tissueand the fragment coding for AD7c-NTP identified by conventionalDNA-hybridization techniques (Southern, J. Mol. Biol. 98:503-517(1975)). Animals positive for the AD7c-NTP gene are further bred toexpand the colonies of AD7c-NTP mice. General and specific examples ofmethods of preparing transgenic animals are disclosed in U.S. Pat. Nos.5,602,299, 5,366,894, 5,464,758, 5,569,827, WO96/40896 (U.S. applicationSer. No. 08/480,653); WO96/40895 (U.S. application Ser. Nos. 08/486,018and 08/486,536); WO93/14200 (U.S. application Ser. Nos. 07/817,584 and07/915,469); WO95/03397 (U.S. application Ser. No. 08/096,944);WO95/25792 (U.S. application Ser. No. 08/215,083); EP 0 717 105 (U.S.application Ser. No. 08/358,627); and Hogan et al., Manipulating theMouse Embryo, Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.,1986); Hammer et al., Cell 63:1099-1112 (1990).

Once obtained, the transgenic animals which contain the AD7c-NTP may beanalyzed by immunohistology for evidence of AD7c-NTP expression as wellas for evidence of neuronal or neuritic abnormalities associated withAlzheimer's disease, neuroectodermal tumors, malignant astrocytomas andglioblastomas. Sections of the brains may be stained with antibodiesspecific for AD7c-NTP, either monoclonal or polyclonal.

The invention also relates to an in vitro method for screening candidatedrugs that are potentially useful for the treatment or prevention ofAlzheimer's disease, neuroectodermal tumors, malignant astrocytomas, andglioblastomas, which comprises

-   -   (a) contacting a candidate drug with a host transfected with a        DNA construct, wherein the DNA construct comprises a DNA        molecule of Seq. ID No. 1 or a DNA molecule that is at least 90%        homologous thereto, and wherein said host over expresses the        protein coded for by said DNA molecule, and    -   (b) detecting at least one of the following:        -   (i) the suppression or prevention of expression of the            protein;        -   (ii) the increased degradation of the protein; or        -   (iii) the reduction of frequency of at least one of neuritic            sprouting, nerve cell death, degenerating neurons,            neurofibrillary tangles, or irregular swollen neurites and            axons in the host;

due to the drug candidate.

In a preferred embodiment, the host is a transgenic animal. In anotherpreferred embodiment, the host is a cell in vitro. The suppression orprevention of expression, and the increased degradation of the proteinsuch as AD7c-NTP may be detected with antibodies specific for AD7c-NTP.Monoclonal and polyclonal antibodies which are specific for AD7c-NTP aswell as methods for the qualitative and quantitative detection ofAD7c-NTP are described herein as well as in WO94/23756 and U.S.application Ser. No. 08/340,426. Such testing may be carried out on CSFof the transgenic animal or by immunohistochemical staining of a tissuesection from the brain of the animal. In addition, such testing may becarried out by Western blot analysis, ELISA or RIA.

Immunohistochemical staining may also be carried out to determine thefrequency of at least one of neuritic sprouting, nerve cell death,degenerating neurons, neurofibrillary tangles, or irregular swollenneurites and axons in the animal. Since in general the animal will haveto be sacrificed, a pool of test and control transgenic animals shouldbe tested. After sacrifice, the relative frequency of neuriticsprouting, nerve cell death, degenerating neurons, neurofibrillarytangles, or irregular swollen neurites and axons is determined for bothgroups. If the test group exhibits a reduced frequency of neuriticsprouting, nerve cell death, degenerating neurons, neurofibrillarytangles, or irregular swollen neurites and axons, the drug may beconsidered promising for the treatment or prevention of Alzheimer'sdisease, neuroectodermal tumors, malignant astrocytomas, orglioblastomas.

When the host is a transgenic animal, the effect of a drug candidate mayalso be tested by behavioral tests which are designed to assess learningand memory deficits. An example of such a test is the Morris water mazedisclosed by Morris, Learn Motivat. 12:239-260 (1981) and WO96/40895.

In the practice of the method of the invention, the candidate drug isadministered to the transgenic animals or introduced into the culturemedia of cells derived from the animals or cells transfected with theDNA construct of the invention. The candidate drug may be administeredover a period of time and in various dosages, and the animals or animalcells tested for alterations in AD7-c NTP expression, nerve celldegradation or histopathology. In case of transgenic animals, they mayalso be tested for improvement in behavior tests.

When cells are to be tested in vitro for the effect of the candidatedrug, they are grown in a growth conducive medium and the mediumreplaced with a media containing the candidate drug. Wide varieties ofmedias which promote growth of practically any cell type arecommercially available, for example, from Life Technologies, Inc.(Gaithersburg, Md.). If the candidate drug is only sparingly soluble inthe media, a stock solution may be prepared in dimethyl sulfoxide(DMSO). The DMSO solution is then admixed with the media. Preferably,the DMSO concentration in the media does not exceed 0.5%, preferably,0.1%. The cells are then incubated in the presence of thedrug-containing media for a preselected time period (e.g. 2-10 hours) ata preselected temperature, for example, about 37° C. At the end of thistime period, the media may again be removed and fresh media containingthe candidate drug is added. The cells are then incubated for a secondpreselected time period (e.g. 2-16 hours). This procedure can berepeated as necessary to achieve a significant result.

After the treatment period, the cells are tested either for the level ofNTP expression and/or, if the cells are neuronal cells, examined for thepresence and/or frequency of neuritic sprouting, nerve cell death,degenerating neurons, neurofibrillary tangles, or irregular swollenneurites and axons. In order to test for the level of NTP expression,immunohistochemical staining may be carried out as described in theExamples. Alternatively, the plates containing the cells may becentrifuged to pellet cellular debris from the medium, and a sample ofthe media tested for the NTP concentration. The concentration of NTP maybe determined by ELISA with an antibody which is specific for NTP.Methods for carrying out such assays are disclosed in WO94/10569 and arewell known to those of ordinary skill in the art. The concentration ofNTP in the test cells/media is then compared to the concentration ofcontrol cells that have been treated the same way except that the mediadoes not contain the candidate drug (but may contain the same level ofDMSO). The results of the ELISA are fit to a standard curve andexpressed as ng/mL NTP. See WO96/40895.

In a preferred in vitro model system, the AD7c-NTP is cloned into aLac-Switch inducible system and stably transfected into neuronal cells(e.g., PNET2 (CYZ), SH-Sy5y and hNT2). AD7c-NTP may be the full lengthcDNA or a CAT reporter gene construct. Protein expression is induciblewith 1-5 mM IPTG. Cultures may be examined for cell death, neuriticsprouting and the corresponding changes in gene expression associatedwith these or other AD-related phenomena. Analytical methods availablefor analysis include, but are not limited to, viability (Crystal violet)and metabolic (MTT) assays, western blot and immunocytochemicalstaining, Microtiter ImmunoCytochemical ELISA (MICE) assay, apoptosisDNA fragmentation assays (ladder, end-labeling, Hoechst staining andTUNEL assay) and CAT assay for gene expression studies.

The effects of candidate drugs on the toxicity of NTP to neuronal cellscan also be determined in primary rat cortical cell cultures accordingto WO96/40895, or with human fetal brain tissue, or differentiatedneuronal cell lines such as hNT2 and SH-Sy5y cell lines. Alternatively,neuronal cells transformed with and expressing the gene coding forAD7c-NTP as described herein may be used.

Antisense oligonucleotides have been described as naturally occurringbiological inhibitors of gene expression in both prokaryotes (Mizuno etal., Proc. Natl. Acad. Sci. USA 81:1966-1970 (1984)) and eukaryotes(Heywood, Nucleic Acids Res. 14:6771-6772 (1986)), and these sequencespresumably function by hybridizing to complementary mRNA sequences,resulting in hybridization arrest of translation (Paterson, et al.,Proc. Natl. Acad. Sci. USA, 74:4370-4374 (1987)).

Antisense oligonucleotides are short synthetic DNA or RNA nucleotidemolecules formulated to be complementary to a specific gene or RNAmessage. Through the binding of these oligomers to a target DNA or mRNAsequence, transcription or translation of the gene can be selectivelyblocked and the disease process generated by that gene can be halted(see, for example, Jack Cohen, Oligodeoxynucleotides, AntisenseInhibitors of Gene Expression, CRC Press (1989)). The cytoplasmiclocation of mRNA provides a target considered to be readily accessibleto antisense oligodeoxynucleotides entering the cell; hence much of thework in the field has focused on RNA as a target. Currently, the use ofantisense oligodeoxynucleotides provides a useful tool for exploringregulation of gene expression in vitro and in tissue culture(Rothenberg, et al., J. Natl. Cancer Inst. 81:1539-1544 (1989)).

Antisense therapy is the administration of exogenous oligonucleotideswhich bind to a target polynucleotide located within the cells. Forexample, antisense oligonucleotides may be administered systemically foranticancer therapy (WO 90/09180). AD7c-NTP is produced byneuroectodernal tumor cells, malignant astrocytoma cells, glioblastomacells, and in relatively high concentrations (i.e, relative to controls)in brain tissue of AD patients. Thus, AD7c-NTP antisenseoligonucleotides of the present invention may be active in treatmentagainst AD, as well as neuroectodermal tumors, malignant astrocytomas,and glioblastomas.

As discussed above, the invention also relates to the correct amino acidand nucleotide sequence for NTP. Thus, the invention also relates toantisense oligonucleotides which are complementary to the mRNA which maybe transcribed from Seq. ID No. 1, wherein said oligonucleotidescorrespond to regions of the NTP gene that were incorrectly sequenced inWO94/23756 and WO96/15272, e.g. in the region including nucleotides150-1139 (nucleotides 1-148 of FIG. 16R of published application;nucleotides 1-149 of Seq. ID No. 1 of the present application: werecorrectly sequenced). This incorrect sequence is present in Seq. ID Nos.3 and 4. Thus, the invention relates to an antisense oligonucleotidewhich is complementary to an NTP mRNA sequence corresponding tonucleotides 150-1139 of Seq. ID No. 1. Preferebly, the oligonucleotidescorrespond to regions including nucleotides selected from the groupconsisting of nucleotides 150, 194-195, 240-241, 243, 244, 255-256,266-267, 269-271, 276, 267, 279-280, 293-295, 338-340, 411, 459,532-533, 591, 633-644, 795-797, 828, 853-854, 876-877, 883, 884-885,898, 976, 979-980, 999, 1037, 1043-1044, 1092-1096, 1099, and 1116-1119of Seq. ID No. 1. More preferably, the invention is related to anantisense oligonucieotide sequence selected from the group consistingof:

5′ TTC ATC CTG GGT AAG AGT GGG ACA CCT GTG (Seq. ID No.9); 5′ TGG TGCATG TCT TTG GTC CCA GCT AC (Seq. ID No.10); and 5′ ATC AAC CTG GCG AACATG GTG AAC CCC ATC (Seq. ID No. 11).

Also preferably, the sequence is a 15 to 40-mer, more preferably, a 15to 30-mer. Also preferably, the antisense oligonucleotide it aphosphorothioate or one of the other oligonucleotide derivativesmentioned above. Also preferred are antisense oligonucleotides which arecomplementary to an NTP nucleic acid sequence and which arenonhomologous to PTP nucleic acid sequences and that correspond toregions that were incorrectly sequenced in the past, as well aspharmaceutical compositions comprising such oligonucleotides and apharmaceutically acceptable carrier.

Included as well in the present invention are pharmaceuticalcompositions comprising an effective amount of at least one of the NTPantisense oligonucleotides of the invention in combination with apharmaceutically acceptable carrier. In one embodiment, a single NTPantisense oligonucleotide is utilized. In another embodiment, two NTPantisense oligonucleotides are utilized which are complementary toadjacent regions of the NTP DNA. Administration of two NTP antisenseoligonucleotides which are complementary to adjacent regions of the DNAor corresponding mRNA may allow for more efficient inhibition of NTPgenomic transcription or mRNA translation, resulting in more effectiveinhibition of NTP production.

Preferably, the NTP antisense oligonucleotide is coadministered with anagent which enhances the uptake of the antisense molecule by the cells.For example, the NTP antisense oligonucleotide may be combined with alipophilic cationic compound which may be in the form of liposomes. Theuse of liposomes to introduce nucleotides into cells is taught, forexample, in U.S. Pat. Nos. 4,897,355 and 4,394,448. See also U.S. Pat.Nos. 4,235,871, 4,231,877, 4,224,179, 4,753,788, 4,673,567, 4,247,411,4,814,270 for general methods of preparing liposomes comprisingbiological materials.

Alternatively, the NTP antisense oligonucleotide may be combined with alipophilic carrier such as any one of a number of sterols includingcholesterol, cholate and deoxycholic acid. A preferred sterol ischolesterol.

In addition, the NTP antisense oligonucleotide may be conjugated to apeptide that is ingested by cells. Examples of useful peptides includepeptide hormones, antigens or antibodies, and peptide toxins. Bychoosing a peptide that is selectively taken up by the neoplastic cells,specific delivery of the antisense agent may be effected. The NTPantisense oligonucleotide may be covalently bound via the 5′OH group byformation of an activated aminoalkyl derivative. The peptide of choicemay then be covalently attached to the activated NTP antisenseoligonucleotide via an amino and sulfhydryl reactive hetero bifunctionalreagent. The latter is bound to a cysteine residue present in thepeptide. Upon exposure of cells to the NTP antisense oligonucleotidebound to the peptide, the peptidyl antisense agent is endocytosed andthe NTP antisense oligonucleotide binds to the target NTP mRNA toinhibit translation (Haralambid et al., WO 8903849; Lebleu et aL., EP0263740).

The NTP antisense oligonucleotides and the pharmaceutical compositionsof the present invention may be administered by any means that achievetheir intended purpose. For example, administration may be byparenteral, subcutaneous, intravenous, intramuscular, intra-peritoneal,transdermal, intrathecal or intracranial routes. The dosage administeredwill be dependent upon the age, health, and weight of the recipient,kind of concurrent treatment, if any, frequency of treatment, and thenature of the effect desired.

Compositions within the scope of this invention include all compositionswherein the NTP antisense oligonucleotide is contained in an amounteffective to achieve inhibition of proliferation and/or stimulatedifferentiation of the subject cancer cells, or alleviate AD. Whileindividual needs vary, determination of optimal ranges of effectiveamounts of each component is with the skill of the art. Typically, theNTP antisense oligonucleotide may be administered to mammals, e.g.humans, at a dose of 0.005 to 1 mg/kg/day, or an equivalent amount ofthe pharmaceutically acceptable salt thereof, per day of the body weightof the mammal being treated.

Antisense oligonucleotides can be prepared which are designed tointerfere with transcription of the NTP gene by binding transcribedregions of duplex DNA (including introns, exons, or both) and formingtriple helices (U.S. Pat. No. 5,594,121, U.S. Pat. No. 5,591,607,WO96/35706, WO96/32474, WO94/17091, WO94/01550, WO 91/06626, WO92/10590). Preferred oligonucleotides for triple helix formation areoligonucleotides which have inverted polarities for at least two regionsof the oligonucleotide (Id.). Such oligonucleotides comprise tandemsequences of opposite polarity such as 3′ - - - 5′-L-5′ - - - 3′, or5′ - - - 3′-L-3′ - - - 5′, wherein L represents a 0-10 baseoligonucleotide linkage between oligonucleotides. The inverted polarityform stabilizes single-stranded oligonucleotides to exonucleasedegradation (Froehler et al., supra). Preferred oligonucleotides arenonhomologous to PTP nucleic acid sequences, and correspond to regionsthat were incorrectly sequenced in the past. The invention is related aswell to pharmaceutical compositions comprising sucholigodeoxynucleotides and a pharmaceutically acceptable carrier.

In therapeutic application, the triple helix-forming oligonucleotidescan be formulated in pharmaceutical preparations for a variety of modesof administration, including systemic or localized administration, asdescribed above.

The antisense oligonucleotides and triple helix-forming oligonucleotidesof the present invention may be prepared according to any of the methodsthat are well known to those of ordinary skill in the art, includingmethods of solid phase synthesis and other methods as disclosed in thepublications, patents and patent applications cited herein.

The invention is also directed to ribozymes comprising a target sequencewhich is complementary to an NTP sequence of Seq. ID No. 1 andnonhomologous to PTP nucleic acid sequences and that correspond toregions that were incorrectly sequenced in the past, as well aspharmaceutical compositions comprising such ribozymes and apharmaceutically acceptable carrier.

Ribozymes provide an alternative method to inhibit mRNA function.Ribozymes may be RNA enzymes, self-splicing RNAs, and self-cleaving RNAs(Cech et al., Journal of Biological Chemistry 267:17479-17482 (1992)).It is possible to construct de novo ribozymes which have an endonucleaseactivity directed in trans to a certain target sequence. Since theseribozymes can act on various sequences, ribozymes can be designed forvirtually any RNA substrate. Thus, ribozymes are very flexible tools forinhibiting the expression of specific genes and provide an alternativeto antisense constructs.

A ribozyme against chloramphenicol acetyltransferase mRNA has beensuccessfully constructed (Haseloff et al. Nature 334:585-591 (1988);Uhlenbeck et al., Nature 328:596-600 (1987)). The ribozyme containsthree structural domains: 1) a highly conserved region of nucleotideswhich flank the cleavage site in the 5′ direction; 2) the highlyconserved sequences contained in naturally occurring cleavage domains ofribozymes, forming a base-paired stem; and 3) the regions which flankthe cleavage site on both sides and ensure the exact arrangement of theribozyme in relation to the cleavage site and the cohesion of thesubstrate and enzyme. RNA enzymes constructed according to this modelhave already proved suitable in vitro for the specific cleaving of RNAsequences (Haseloff et al., supra). Examples of such regions include theantisense oligonucleotides mentioned above.

Alternatively, hairpin ribozymes may be used in which the active site isderived from the minus strand of the satellite RNA of tobacco ring spotvirus (Hampel et al., Biochemistry 28:4929-4933 (1989)). Recently, ahairpin ribozyme was designed which cleaves human immunodeficiency virustype 1 RNA (Ojwang et al., Proc. Natl. Acad. Sci. USA 89:10802-10806(1992)). Other self-cleaving RNA activities are associated withhepatitis delta virus (Kuo et al., J. Virol. 62:4429-4444 (1988)). Seealso U.S. Pat. No. 5,574,143 for methods of preparing and usingribozymes. Preferably, the NTP ribozyme molecule of the presentinvention is designed based upon the chloramphenicol acetyltransferaseribozyme or hairpin ribozymes, described above. Alternatively, NTPribozyme molecules are designed as described by Eckstein et al.(International Publication No. WO 92/07065) who disclose catalyticallyactive ribozyme constructions which have increased stability againstchemical and enzymatic degradation, and thus are useful as therapeuticagents.

In an alternative approach, an external guide sequence (EGS) can beconstructed for directing the endogenous ribozyme, RNase P, tointracellular NTP mRNA, which is subsequently cleaved by the cellularribozyme (Altman et al., U.S. Pat. No. 5,168,053). Preferably, the NTPEGS comprises a ten to fifteen nucleotide sequence complementary toAD7c-NTP mRNA (corresponding to the miss-sequenced regions) and a3′-NCCA nucleotide sequence, wherein N is preferably a purine (Id.).After NTP EGS molecules are delivered to cells, as described below, themolecules bind to the targeted NTP mRNA species by forming base pairsbetween the NTP mRNA and the complementary NTP EGS sequences, thuspromoting cleavage of NTP mRNA by RNase P at the nucleotide at the 5′side of the base-paired region (Id.).

Examples of such external guide sequences are:

CAC TGC ACT TNC CA (Seq. ID No.12) CCA GGT GTA GNC CA (Seq. ID No.13)CAA GGT CCA GNC CA (Seq. ID No.14)

Included as well in the present invention are pharmaceuticalcompositions comprising an effective amount of at least one NTPantisense oligonucleotide, triple helix-forming oligonucleotide, NTPribozyme or NTP EGS of the invention in combination with apharmaceutically acceptable carrier. Preferably, the NTP antisenseoligonucleotide, triple helix-forming oligonucleotide, NTP ribozyme orNTP EGS is coadministered with an agent which enhances the uptake of theNTP antisense oligonucleotide, triple helix-forming oligonucleotide,ribozyme or NTP EGS molecule by the cells. For example, the NTPantisense oligonucleotide, triple helix-forming oligonucleotide, NTPribozyme or NTP EGS may be combined with a lipophilic cationic compoundwhich may be in the form of liposomes, as described above.Alternatively, the NTP antisense oligonucleotide, NTP triplehelix-forming oligonucleotide, NTP ribozyme or NTP EGS may be combinedwith a lipophilic carrier such as any one of a number of sterolsincluding cholesterol, cholate and deoxycholic acid. A preferred sterolis cholesterol.

The NTP antisense oligonucleotide, NTP triple helix-formingoligonucleotide, NTP ribozyme or NTP EGS, and the pharmaceuticalcompositions of the present invention may be administered by any meansthat achieve their intended purpose. For example, administration may beby parenteral, subcutaneous, intravenous, intramuscular,intra-peritoneal, transdermal, intrathecal or intracranial routes. Thedosage administered will be dependent upon the age, health, and weightof the recipient, kind of concurrent treatment, if any, frequency oftreatment, and the nature of the effect desired. For example, as much as700 milligrams of antisense oligodeoxynucleotide has been administeredintravenously to a patient over a course of 10 days (i.e., 0.05mg/kg/hour) without signs of toxicity (Sterling, “Systemic AntisenseTreatment Reported,” Genetic Engineering News 12(12):1, 28 (1992)).

Compositions within the scope of this invention include all compositionswherein the NTP antisense oligonucleotide, NTP triple helix-formingoligonucleotide, NTP ribozyme or NTP EGS is contained in an amount whichis effective to achieve inhibition of proliferation and/or stimulatedifferentiation of the subject cancer cells, or alleviate AD. Whileindividual needs vary, determination of optimal ranges of effectiveamounts of each component is with the skill of the art.

In addition to administering the NTP antisense oligonucleotides, triplehelix-forming oligonucleotides, ribozymes, or NTP EGS as a raw chemicalin solution, the therapeutic molecules may be administered as part of apharmaceutical preparation containing suitable pharmaceuticallyacceptable carriers comprising excipients and auxiliaries whichfacilitate processing of the NTP antisense oligonucleotide, triplehelix-forming oligonucleotide, ribozyme, or NTP EGS into preparationswhich can be used pharmaceutically. Suitable formulations for parenteraladministration include aqueous solutions of the NTP antisenseoligonucleotides, NTP triple helix-forming oligonucleotides, NTPribozymes, NTP EGS in water-soluble form, for example, water-solublesalts. In addition, suspensions of the active compounds as appropriateoily injection suspensions may be administered. Suitable lipophilicsolvents or vehicles include fatty oils, for example, sesame oil, orsynthetic fatty acid esters, for example, ethyl oleate or triglycerides.Aqueous injection suspensions may contain substances which increase theviscosity of the suspension include, for example, sodium carboxymethylcellulose, sorbitol, and/or dextran. Optionally, the suspension may alsocontain stabilizers.

Alternatively, NTP antisense oligonucleotides, NTP triple helix-formingoligonucleotides, NTP ribozymes, and NTP EGS can be coded by DNAconstructs which are administered in the form of virions, which arepreferably incapable of replicating in vivo (see, for example, Taylor,WO 92/06693). For example, such DNA constructs may be administered usingherpes-based viruses (Gage et al., U.S. Pat. No. 5,082,670).Alternatively, NTP antisense oligonucleotides, NTP triple helix-formingoligonucleotides, NTP ribozymes, and NTP EGS can be coded by RNAconstructs which are administered in the form of virions, such asretroviruses. The preparation of retroviral vectors is well known in theart (see, for example, Brown et al., “Retroviral Vectors,” in DNACloning: A Practical Approach, Volume 3, IRL Press, Washington, D.C.(1987)).

According to the present invention, gene therapy can be used toalleviate AD by inhibiting the inappropriate expression of a particularform of NTP. Moreover, gene therapy can be used to alleviate AD byproviding the appropriate expression level of a particular form of NTP.In this case, particular NTP nucleic acid sequences may be coded by DNAor RNA constructs which are administered in the form of viruses, asdescribed above. Alternatively, “donor cells” may be modified in vitrousing viral or retroviral vectors containing NTP sequences, or usingother well known techniques of introducing foreign DNA into cells (see,for example, Sambrook et al., supra). Such donor cells includefibroblast cells, neuronal cells, glial cells, and connective tissuecells (Gage et al., supra). Following genetic manipulation, the donorcells are grafted into the central nervous system and thus, thegenetically-modified cells provide the therapeutic form of NTP (Id.).

Moreover, such virions may be introduced into the blood stream fordelivery to the brain. This is accomplished through the osmoticdisruption of the blood brain barrier prior to administration of thevirions (see, for example, Neuwelt, U.S. Pat. No. 4,866,042). The bloodbrain barrier may be disrupted by administration of a pharmaceuticallyeffective, nontoxic hypertonic solution, such as mannitol, arabinose, orglycerol (Id.).

Having now generally described the invention, the same will be morereadily understood through reference to the following Examples which areprovided by way of illustration, and are not intended to be limiting ofthe present invention, unless specified.

EXAMPLES Example 1 Isolation of the AD7c-NTP cDNA

A cDNA library was prepared commercially (Invitrogen Corp., San Diego,Calif.) using RNA extracted from the temporal lobe of an individual withend-stage AD. The library was ligated into the pcDNA2 vector (InVitrogen). To isolate the AD7c-NTP gene, approximately 5×10⁵ transformedand IPTG induced (Sambrook, J. et al. “Molecular Cloning. A LaboratoryManual,” Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.)E. coli colonies were screened using polyclonal antibodies to human PTP(Gross, J. et al., “Isolation, Characterization, and Distribution of anUnusual Pancreatic Human Secretory Protein,” J. Clin. Invest.76:2115-2126 (1985)), followed by radiolabeled anti-human IgG (Amersham,Arlington Heights, Ill.) (Sambrook, J. et al. (1989); and Ausubel, F. M.et al., “Current Protocols in Molecular Biology,” New York, N.Y., JohnWiley & Sons (1988)). Restriction endonuclease fragments (XhoI-PstI;PstI-PvuII; PvuII-HindIII) of AD7c-NTP were subcloned into pGem7(Promega Corp., Madison, Wis.), and the nucleotide sequence of bothstrands was determined by the dideoxy chain termination method using T7DNA polymerase (Ausubel, F. M. et al. (1988)). Additional gene specificprimers were generated to generate sequences that overlapped thefragments. The DNA sequence was assembled with the MacVector Softwareversion 4.5 and analyzed using a Sequence Analysis Software of theGenetics Computer Group version 7.3 as implemented on a MicroVax IIcomputer. Database searches were performed using the BLAST networkservice of the National Center for Biotechnology Information.

Characteristics of the AD7c-NTP cDNA Isolated from an AD Brain Library

The AD7c-NTP cDNA contains 1442 nucleotides and begins with an oligo-dTtrack. The nucleotide sequence contains an 1125-nucleotide open readingframe starting with the first AUG codon, and a 302-nucleotideuntranslated sequence that contains an AATAAA polyadenylation signal(FIG. 1). Bestfit and GAP analysis revealed the presence of fourAlu-type sequences embedded in the open reading frame (nucleotides1-170, 423-593, 595-765, and 898-1068), and a near-duplication (85%identical) of the first 450 nucleotides starting at nucleotide 898.BLAST database comparisons disclosed 3 regions of significance (67-89%)homology to the Huntington's disease region, chromosome 4pl6.3 (Gusella,J. F. et al., “A Polymorphic DNA Marker Genetically Linked toHuntington's Disease,” Nature 306:24-238 (1983)) (FIG. 1), but noalignment with the IT15 Huntington cDNA which contains longer thannormal (CAG)_(n) repeats in individuals with Huntington's disease (TheHuntington's Disease Collaborative Research Group, “A Novel GeneContaining a Trinucleotide Repeat that is Expanded and Unstable onHuntington's Disease Chromosomes,” Cell 72:971-983 (1993)).

The translated 375 amino acid sequence has a predicted molecular weightof 41,718 and estimated pI of 9.89, and is rich in Ser (11.7%) and Pro(8.8%) residues. Kyte-Doolittle and Chou-Fasman hydrophilicity andHopp-Woods surface probability profiles predict a 15 amino acidhydrophobic leader sequence, and 7 membrane-spanning regions.Corresponding with the organization of the cDNA, subsequent analysis ofthe protein revealed four 83% to 91% identical repeated (once or twice)antigenic domains between 9 and 23 amino acids in length (FIG. 1).Protein subsequent analysis demonstrated 21 cAMP, calmodulin-dependentprotein kinase II, protein kinase C, or glycogen synthase kinase 3phosphorylation sites, and one myristyration site. In addition, a singletgf motif (Residues #44-#53) was detected. Comparison of the AD7c-NTPamino acid sequence with the genebank database revealed four regions ofsignificant homology to the β-subunit of integrin (72%-80%), thealternatively spliced A4 form of the neurofibromatosis 2 gene (72%-81%),myelin oligodendroglial glycoprotein-16 precursor protein (70%-76%),human integral membrane protein (55%-85%), and human decay acceleratingfactor 2 precursor (62%-68%), and two regions with homology to the c-relprotooncogene transforming protein (Residues 56-84: 65%; Residues287-295:88%) (FIG. 1). Residues 5-24 are 75% identical to a region ofthe IGF1/insulin receptor hybrid, and residues 4-24, 47-79, 109-132,227-261, and 227-360 exhibit 57% to 76% identity with the humantransformation-related protein. In addition, two serine/threonine kinaseprotein domains (Residues 6-48, and 272-294) were identified.

The in vitro translated protein and pTrcHis-AD7c-NTP recombinant proteinpurified by metal chelate chromatography and cleaved from the fusionpartner had molecular masses of ˜39-42 kD by SDS-PAGE or Western blotanalysis (FIG. 2). In addition, in Bosc cells transfected with theAD7c-NTP cDNA ligated into the pcDNA3 vector (Invitrogen, San Diego,Calif.), a single ˜39-42 kD protein was detected by Western blotanalysis using the N314 monoclonal antibody. In two-siteimmunoradiometric assays and immunoblotting studies, the AD7c-NTPrecombinant protein exhibited specific immunoreactive binding with allof the polyclonal and monoclonal antibodies generated with purifiedpTrcHis-AD7c-NTP recombinant protein. No immunoreactivity with AD7c-NTPwas detected using pre-immune rabbit sera, non-relevant rabbitpolyclonal antibodies to GAP-43, or non-relevant monoclonal antibodiesto Dengue virus or FB50 (FIG. 2).

Example 2 In Vitro Expression of AD7c-NTP

Antisense and sense cRNAs were transcribed from AD7c-NTP cDNA plasmidwith KpnI and XhoI, respectively. The cRNA transcripts were translatedin a rabbit reticulocyte lysate system (Stratagene, La Jolla, Calif.) inthe presence of [³⁵S]methionine (Dupont-New England Nuclear, Boston,Mass.), and the products of in vitro translation were analyzed bySDS-PAGE and autoradiography. The AD7c-NTP cDNA was ligated into thepTrcHis expression vector (Invitrogen Corp., San Diego, Calif.) whichencodes a 5 N 6-His Tag sequence used to isolate the fusion protein bymetal chelate chromatography. Recombinant fusion protein induction intransformed E. coli was achieved by the addition of 1 mM IPTG during logphase growth. The fusion protein was affinity purified (Ausubel, F. M.et al. (1988)) using ProBond resin (Invitrogen Corp., San Diego,Calif.), and detected by Western blot analysis (Harlow, E. and Lane, D.,“Antibodies: A Laboratory Manual,” Cold Spring Harbor Laboratory, ColdSpring Harbor, N.Y. (1988)) with antibodies to do T7-tag fusion partner(Novogen). The tag was then cleaved with entrokinase to give theAD7c-NTP protein. (Ausubel, R. M et al. (eds.) in Current Protocols inMolecular Biology, John Wiley & Sons, Inc., New York, N.Y., 1994.

Example 3 Generation of Polyclonal and Monoclonal Antibodies toRecombinant AD7c-NTP

Polyclonal antibodies were generated in rabbits immunized with affinitypurified recombinant AD7c-NTP protein. Monoclonal antibodies weregenerated in Balb/c mice immunized intraperitoneally with 50 μg ofpurified recombinant AD7c-NTP protein emulsified in complete Freund'sadjuvant (Harlow, E. and Lane, D. (1988); and Wands, J. R. and Zurawski,V. R., Jr., “High Affinity Monoclonal Antibodies to Hepatitis B surfaceAntigen (HBsAg) produced by Somatic Cell Hybrids,” Gastroeneology80I:225-232 (1981)). The mice were boosted 6 to 10 weeks later, with 10μg AD7c-NTP by tail vein injection. Spleenocytes were fused with SP-0myeloma cells (Harlow, E. and Lane, D. (1988) and Wands, J. R. andZurawski, V. R., Jr. (1981)). The cells were grown in HAT medium, andhybridomas producing anti-AD7c-NTP antibody were identified by solidphase immunoassay (Bellet, D. H. etal., “Sensitive and Specific Assayfor Human Chorionic Gonadotropin Based on Anti-Peptide andAnti-Glycoprotein Monoclonal Antibodies: Construction and ClinicalImplications,” J. Clin. Endocrinol. Metabol. 63:1319-1327 (1988)). Thebinding specificity of the immunoglobulin fractions of polyclonal immunesera and the hybridoma supernatants was confirmed by radioimmunoassay(RIA) and Western blot analysis with recombinant AD7c-NTP, and byWestern blot analysis and immunohistochemical staining of AD and agedcontrol brains. In a panel of 25 hybridomas, 3 MoAbs exhibited similarlevels of immunoreactivity with purified native PTP and recombinantAD7c-NTP, and therefore were further characterized (Table 1).

TABLE 1 Profiles of Immunoreactivity Exhibited by AD7c-NTP MonoclonalAntibodies AD Distribution of Antibody Western Blot ICC* Specific**Labeling in AD Brains N2B10 Y: Reducing Negative N/A None N2I5 Y:Reducing Negative N/A None N2J1 Yes ++ Yes Neurophil threads, irregularneurites, axons N2R1 No Negative N/A None N2S6 Y: Reducing ++++ YesNeurons N2T8 Y: Reducing ++++ Yes Degenerating neurons, NFT, irregularneurites N2U6 Yes +++ Yes Neurophil threads, NFT N3A13 No + No NoneN3C11 No ++ No None N3D12 No + No None N3I4 Y: Non- Negative N/A Nonereducing N2-36 No + Yes NFT, Swollen neurites N2-22-11 No Negative N/ANone Polyclonal Yes ++++ Yes† Degenerating neurons, irregular neurites*ICC = Immunocytochemistry; NFT = neurofibrillary tangles **AD-specific:Immunoreactivity only detected in histologically normal neutrons andfibers in AD tissue sections (N2S6), or in degenerating neuronal cellbodies and processes detected in AD. † = following formic acid treatmentonly.

Profiles of AD7c-NTP Immunoreactivity Revealed with MoAbs (Table 1): Thefindings summarized below are representative of the observations made in6 end-stage AD and 5 aged control brains. Twenty-five of the AD7c-NTPMoAbs were characterized by immunocytochemical staining. Table 1 detailsfeatures of 13 AD7c-NTP MoAbs. The other 12 MoAbs were excluded from thelist because either they were not suitable for immunocytochemicalstaining and Western immunoblot studies due to low-level binding (N=9),or they exhibited cross-immunoreactivity with pancreatic thread protein(N=3). Among the 13 AD7c-NTP MoAbs that were further characterized, only8 exhibited immunoreactivity in neuronal perikarya, neuropil fibers,white matter fibers (axons), or AD neurodegenerative lesions. The other5 were non-immunoreactive in histologic sections.

In Table 1, AD-specific binding refers to the detection of degeneratingneurons, neurofibrillary tangles, irregular swollen neurites and axons,or immunoreactivity in histologically intact neurons in AD but notcontrol brains. Four AD7c-NTP MoAbs (N2-36, N3-C11, N2S6, N2-T8)exhibited intense degrees of immunocytochemical staining in corticalneurons, particularly pyramidal cells in layers 3 and 5. Two MoAbs(N2-U6, N2-S6) prominently labeled neuropil and white matter fibers(axons), and 5 (N2-U6, N3-C11, N2-S6, N2-T8, N2-J1) detected A2B5+ andGFAP+ protoplasmic (Type 2) astrocytes in the cerebral cortex and whitematter. Two AD7c-NTP MoAbs (N2-U6 and N2-T8) exhibited intense labelingof cortical neurons and swollen, irregular (dystrophic) neuropilneurites in AD, but low-level or absent labeling in aged control brains.Most striking was the immunoreactivity observed in AD-associatedneurodegenerative lesions using the N2-36, N2-T8, N2-U6 MoAbs. N2-T8detected intracellular neurofibrillary tangles as well as degeneratedneurons without neurofibrillary tangles; N3-D12, N2-T8, and N2-J1labeled swollen dystrophic axons and fine neuritic processes,particularly in superficial layers of the cerebral cortex; and N2-U6 andN2-J1 labeled wavy irregular threadlike structures detected only in ADbrains. N2J1 very prominently labeled irregular threadlike structures,dystrophic neurites, and swollen axons, but exhibited minimal labelingof neuronal perikarya or glial cells. The negative control 5C3 MoAb toHepatitis B virus was not immunoreactive with adjacent sections of thesame brains.

In the Examples which follow, polyclonal and the N3I4, N2J1, and N2U6monoclonal AD7c-NTP antibodies were employed.

Example 4 Human Brain Tissue

Human brain tissue was obtained from the Alzheimer's Disease ResearchCenter brain bank at the Massachusetts General Hospital (MGH-ADRC). Allbrains were harvested within 12 hr of death, and the histopathologicaldiagnosis of AD was rendered using CERAD criteria (Mirra, S. S. et al.,“The Consortium to Establish a Registry for Alzheimer's Disease (CERAD).II. Standardization of the Neuropathological assessment of Alzheimer'sDisease,” Neurology 41:479-486 (1991)). The AD group (N=17) had a meanage of 76.3±8.8 years, a mean brain weight of 1117±101 grams, and a meanpostmortem interval of 7.3±3.9 hours. The control group (N=11) had amean age of 78.0±6.2 years, a mean brain weight of 1274±115 grams, and amean postmortem interval of 8.3±3.6 hours. In addition, 4 cases of earlyprobable AD with cognitive decline and moderate AD histopathologicallesions, and 2 cases of diffuse Lewy body disease (Kosaka, K. “Dementiaand Neuropathology in Lewy Body Disease,” Adv. Neurol. 60:456-463(1993)) (DLBD: an AD-related CNS neurodegenerative disease) werestudied. Fresh frozen frontal and temporal lobe tissue was used forNorthern and Western blot analyses. Post-mortem cerebrospinal fluid(CSF) samples (8 AD; 7 control; 2 DLBD) were used to detect AD7c-NTP byWestern blot analysis. Paraffin-embedded histological sections were usedto localize AD7c-NTP gene expression by in situ hybridization andimmunohistochemical staining.

Example 5 Northern Analysis of AD7c-NTP mRNA Expression

Samples (15 μg) of total RNA isolated (Ausubel, F. M. et al. (1988))from AD and aged control frontal lobe tissue (Brodmann Area 11), andnormal adult human kidney, liver, spleen, gastrointestinal tract,ovaries, fallopian tubes, uterus, thyroid, lung, skeletal muscle, andpancreas, were subjected to Northern hybridization analysis using 2×10⁶dpm/ml of [α³²P]dCTP-labeled AD7c-NTP cDNA probe (specific activity ˜10⁸dpm/μg DNA) generated by the random hexamer method (Ausubel, F. M. etal. (1988)). The blots were subsequently washed in stepwise dilutions of5×SSC (1×SSC is 0.15 M NaCl plus 0.015 M sodium citrate) containing 0.5%SDS (Sambrook, J. et al. (1989); Ausubel, F. M. et al. (1988)), andfinally in 0.1×SSC/0.5% SDS at 65° C. To evaluate RNA loading, the blotswere stripped of probe and re-hybridized with a 10-fold molar excess ofa [γ³²P]ATP-labeled synthetic 30mer corresponding to 18 s ribosomal RNA(de la Monte, S. M. and Bloch, K. D. (1996)). The results were analyzedby autoradiography and densitometry (ImageQuant, Molecular Dynamics,Inc).

Results: AD7c-NTP mRNA Expression in AD and Aged Control Brains

In Northern blot hybridization studies, AD7c-NTP cDNA probes detected1.4 kB and 0.9 kB mRNA transcripts in adult human frontal and temporallobe tissue, but not pancreas, kidney, liver, spleen, gastrointestinaltract (various regions) ovaries, fallopian tubes, uterus, thyroid, lung,skeletal muscle, testis, and thymus were negative. Both 1.4 kB and 0.9kB AD7c-NTP mRNA transcripts were detected in AD and aged controlbrains, but the levels of expression were increased in AD. With valuesnormalized to 18S RNA signals to correct for differences in loading andnon-specific degradation, densitometric analysis of non-saturatedautoradiograms revealed significantly higher mean levels of both the 1.4kB (P<0.01) and the 0.9 kB (P<0.05) AD7c-NTP transcripts in AD comparedwith normal aged control brains.

Example 6 Reverse Transcriptase-Polymerase Chain Reaction Amplification(RT-PCR) Studies

Samples of total RNA (2 μg) isolated from human brain, PNET1 and PNET2human CNS neuronal cell lines (The, I. et al., “Neurofibromatosis type 1Gene Mutations in Neuroblastoma,” Nature Genet. 3:62-66 (1993))(positive controls), SH-Sy5y human neuroblastoma cells (Biedler, J. L.et al., “Morphology and Growth, Tumorigenicity, and Cytogenetics ofHuman Neuroblastoma Cells in Continuous Culture,” Cancer Res.33:2643-2652 (1973)), and human pancreas and liver (negative controls)were reverse transcribed using random hexamer primers (Ausubel, F. M.(1988)) and Superscript™ reverse transcriptase (Gibco-BRL, Grand Island,N.Y.). The cDNA products (10%) were subjected to PCR amplification todetect AD7c-NTP sequences using the primers: (459-480) 5′TGTCCCACTCTTACCCAGGATG [Seq ID No. 5] and (849-826) 5′AAGCAGGCAGATCACAAGGTCCAG [Seq. ID No. 6]. β-actin control primers(Dallman, M. J. and Porter, A. C. G., “Semi-Quantitative PCR for theAnalysis of Gene Expression,” In: PCR A Practical Approach, M. J.McPherson et al. (eds.), IRL Oxford University Press, Oxford, pp.215-224 (1991)) (5′ AATGGATGACGATATCGCTG [Seq. ID No. 7];5′-ATGAGGTAGTCTGTCAGGT [Seq. ID No. 8]) were incorporated into allstudies. Each cycle of PCR amplification consisted of denaturation at95° C. for 30 secs, annealing at 60° C. for 30 secs, and extension at72° C. for 1 min. After 30 cycles and a final 10 minute extension at 72°C., approximately 10 percent of the PCR products were analyzed byagarose gel electrophoresis and Southern hybridization using a[γ³²P]dATP-labeled oligonucleotide probe corresponding to nucleotides702-720 of the AD7c-NTP cDNA. The remaining PCR products wereelectrophoretically fractionated and ligated into PCRII TA cloningvectors (InVitrogen Corp, San Diego, Calif.). The nucleotide sequencesof clones isolated from 6 brain samples were determined by the dideoxychain termination method (Sambrook, J. et al., (1989); Ausubel, F. M.(1988)).

Expression of AD7c-NTP mRNA in human brain was verified by RT-PCRamplification of RNA isolated from 6 AD and 5 aged control brains(frontal lobe). The expected 390 nucleotide PCR product was obtainedwith all samples. The specificity of the PCR products was demonstratedby Southern blot analysis using [³²P]-labeled oligonucleotide probescorresponding to internal sequences, and by determining that the nucleicacid sequences of the 390-nucleotide PCR products cloned from 5 ADbrains were identical to the sequence underlined in FIG. 1. In theRT-PCR amplification studies, AD7c-NTP PCR products were also detectedusing RNA isolated from PNET1, PNET2 and SH-Sy5y neuronal cells, but nothuman pancreas or liver. All samples analyzed yielded positive RT-PCRproducts using the β-actin primers.

Example 7 In Situ Hybridization

Paraffin sections (10 μm thick) of AD and control brains were hybridizedwith antisense and sense (negative control) AD7c-NTP cRNA probes (de laMonte S. M. et al., (1995); de la Monte, S. M. and Bloch, K. D. (1996))generated from cDNA templates linearized with KpnI or XhoI, and labeledwith [11-digoxigenin]UTP using SP6 to T7 DNA dependent RNA polymerase(Melton, D. A. et al. “Efficient in Vitro Synthesis of BiologicallyActive RNA and RNA Hybridization Probes from Plasmids Containing aBacteriophage SP6 Promoter,” Nucl. Acids Res. 12:7035-7056 (1984)).Specifically bound probe was detected with alkalinephosphatase-conjugated sheep F(ab′)₂ anti-digoxigenin(Boehringer-Mannheim Inc.) andX-phosphate/5-bromo-4-chloro-3-indolyl-phosphate/nitro-blue-tetrazolium-chloride (de la Monte, S. M. and Bloch, K. D. (1996)). The probespecificity was confirmed by Northern blot analysis of brain usingidentical cRNA probes labeled with [α³²p]UTP.

Results: Cellular Localization of AD7c-NTP mRNA in Human Brain

In situ hybridization studies using [11-digoxigenin]UTP-labeledantisense cRNA probes demonstrated AD7c-NTP-related mRNA transcripts infrontal (Brodmann Area 11) and temporal (Brodmann Area 21) cortexneurons in both AD (N=6) and aged control (N=4) brains (FIG. 3).However, darkfield microscopy revealed strikingly elevated levels ofAD7c-NTP mRNA expression in both temporal and frontal cortex neurons inAD relative to aged control brains, corresponding with the results ofNorthern blot analysis. Low levels of AD7c-NTP MRNA transcripts werealso detected in cortical and white matter glial cells in AD. AD7c-NTPmRNA transcripts were not detected in cerebral blood vessels, andspecific hybridization signals were not observed in any of the specimenshybridized with digoxigenin-labeled sense strand cRNA probes.

Example 7 Immunodetection of AD7c-NTP Expression

Western immunoblotting studies (Harlow, E. and Lane, D. (1988)) wereperformed using protein extracts (60 μg samples) generated frompostmortem frontal and temporal lobe tissue, and various non-CNS tissueshomogenized in RIPA buffer (Ausubel, F. M. et al. (1988)). In addition,40 μl samples of postmortem or antemortem cerebrospinal fluid wereevaluated by Western blot analysis. The blots were probed with rabbitpolyclonal (1:800) or N3I4, N2U6, or N2J1 mouse monoclonal (5 μg/ml)anti-AD7c-NTP. Antibody binding was detected with horseradishperoxidase-conjugated secondary antibody diluted 1:25,000 (Pierce), andSupersignal enhanced chemiluminescence reagents (Pierce). The levels ofAD7c-NTP expression were quantified by volume densitometric scanning ofthe autoradiograms (ImageQuant; Molecular Dynamics Inc., Sunnyvale,Calif.). Cellular localization of AD7c-NTP immunoreactivity wasdemonstrated in paraffin-embedded histological sections of frontal(Brodmann Area 11) and temporal (Brodmann Area 21) lobe from AD andage-matched control brains. The sections were immunostained by theavidin-biotin horseradish peroxidase complex method (de la Monte, S. M.et al. (1995); and de la Monte, S. M. and Bloch, K. D. (1996)) using theN2J1 and N2U6 AD7c-NTP monoclonal antibodies. Adjacent sections wereimmunostained with monoclonal antibodies to glial fibrillary acidicprotein as a positive control, and with monoclonal antibodies to Denguevirus as a negative control.

Results: Characterization of AD7c-NTP Antibody Binding by Western BlotAnalysis

In Western immunoblotting studies of protein extracted from humanfrontal and temporal lobe tissue, broad ˜39-45 kD bands of AD7c-NTPimmunoreactivity were detected with the polyclonal and 11 of the 25monoclonal antibodies. When the proteins were electrophoreticallyfractionated in 15% Laemmli gels and probed with the N3I4, N2U6, or N2J1monoclonal antibodies, the ˜39-45 kD AD7c-NTP-immunoreactive moleculeswere resolved into 3 or 4 tightly clustered bands (FIG. 2E), possiblyrepresenting different degrees of AD7c-NTP phosphorylation. In addition,the polyclonal and 4 of the monoclonal antibodies detected 18-21 kDAD7c-NTP-immunoreactive proteins in brain (FIG. 2E). Western blotanalysis of non-CNS tissues revealed no specific binding with theAD7c-NTP antibodies.

Example 8 In Vitro Expression Studies

The AD7c-NTP cDNA was ligated into the pcDNA3 mammalian expressionvector which contains a CMV promoter (InVitrogen, San Diego, Calif.).SH-Sy5y cells were transfected with either pcDNA3-AD7c-NTP or pcDNA3(empty vector, negative control), and selected with G418. Stablytransfected cell lines were examiner for growth properties, morphology,and expression of AD7c-NTP. Cell growth was assessed by measuring [³H]thymidine incorporation into DNA and determining the density of viablecells in the cultures. Cells grown in chamberslides were immunostainedusing N3I4 monoclonal antibody. AD7c-NTP expression was also evaluatedby Western blot analysis with the N3I4 antibody.

Results: Over-Expression of AD7c-NTP in Neuronal Cells Leads toApoptosis, Neuritic Sprouting which are Characteristic of Alzheimer'sDisease

Over-expression of AD7c-NTP in SH-Sy5y neuronal cells stably transfectedwith pcDNA3-AD7c-NTP resulted in significantly lower densities of viablecells in the cultures, despite normal or elevated levels of DNAsynthesis (FIG. 5). This result was reproducible in other neuronal cellslines and using other expression vectors. Reduced cell density in thecultures was caused by increased cell death. The attendant increase innuclear p53 expression in AD7c-NTP transfected cells suggests that thecell death is likely to be mediated by apoptosis. Subconfluent culturesof SH-Sy5y cells transfected with pcDNA3 contained round or spindledshaped cells with few or no processes (FIG. 6A). In contrast, SH-Sy5ycells transfected with pcDNA3-AD7c-NTP exhibited extensive neuriticgrowth with fine interconnecting processes detected on most cells (FIGS.6B-6D). In addition, pcDNA3-AD7c-NTP transfected cultures alwayscontained numerous round, refractile floating cells (dead) which failedto exclude Trypan blue dye. Immunocytochemical staining of stationarycultures using the N3I4 monoclonal antibody revealed intense labeling ofthe cell bodies and cell processes of SH-Sy5y cells transfected withpcDNA3-AD7c-NTP (FIGS. 6F and 6G), and absent immunoreactivity inSH-Sy5y cells transfected with pcDNA3 (empty vector) (FIG. 6E). Thesestudies demonstrate that over expression of AD7c-NTP in transfectedneuronal cells promotes neuritic sprouting and cell death, two of themajor features of Alzheimer's disease neurodegeneration. Thus,transfected cell lines and transgenic animals which over-express theAD7c-NTP will be useful for screening drugs that might be effective inreducing AD7c-NTP expression and, thereby, treating or preventing theonset of Alzheimer's disease.

Example 9 AD7c-NTP Protein Expression in AD and Aged Control Brains

Western blot analysis and immunohistochemical staining of AD and agedcontrol brains were performed using the N3I4, N2U6, and N2J1 monoclonalAD7c-NTP antibodies. In AD and aged control brains, ˜39-45 kD proteinswere detected with all 3 monoclonal antibodies. In addition, ˜18-21 kDproteins were detected with the N2U6 and N2J1 antibodies. Densitometricanalysis of the autoradiograms demonstrated significantly higher levelsof the ˜39-45 kD AD7c-NTP in AD relative to aged control frontal lobetissue (FIG. 2D). In addition, expression of the ˜18-21 kDAD7c-NTP-immunoreactive proteins was also increased in AD, but studieshave not yet determined whether these molecules represent cleavageproducts of the ˜39-45 kD AD7c-NTP, or a unique protein encoded byanother cDNA. In a small series, comparisons between early and late ADrevealed higher levels of AD7c-NTP immunoreactivity in brains withend-stage disease (FIG. 2E). Using the N3I4 antibody, Western blotanalysis detected the presence of ˜39-45 kD AD7c-NTP molecules inpostmortem CSF, and higher levels in AD relative to aged control samples(FIG. 2F). Immunohistochemical staining studies with polyclonal andseveral brain-specific monoclonal antibodies localized AD7c-NTPimmunoreactivity in neurons, neuropil fibers, and white matter fibers inAD and control brains. In immunohistochemical staining studies, the N2U6and N2J 1 antibodies exhibited intense immunoreactivity in intact aswell as degenerating cortical neurons and dystrophic neurites in ADbrains, but low-level or absent immunoreactivity in aged control brains(FIG. 4). Omission or pre-adsorption of the primary antibody withrecombinant AD7c-NTP protein, or the application of non-relevant primaryantibody (negative controls) also yielded negative immunostainingresults. All sections of brain exhibited positive immunoreactivity withmonoclonal antibodies to glial fibrillary acidic protein (positivecontrol).

These studies demonstrate elevated levels of AD7c-NTP expression in ADrelative to aged control brains, and abnormal AD7c-NTP gene expressionlocalized in AD brain neurons by in situ hybridization andimmunohistochemical staining. Although two distinct mRNA transcripts andat least two distinct protein species were detected in brain, the levelsof the mRNA and protein corresponding to AD7c-NTP were increased in AD.We have not yet determined whether the smaller transcripts and proteinspecies are distinct, or represent alternately spliced forms of a singlegene. Although the cDNA was isolated from a library prepared with RNAisolated from a single AD brain, the RT-PCR studies confirmed thepresence of identical sequences in 6 different AD brains. Since theAD7c-NTP CDNA exhibits no significant primary sequence homology with thehuman pancreatic protein (Watanabe, T. et al., “Complete NucleotideRepeat that is expanded and Unstable on Huntington's DiseaseChromosomes,” Cell 72:971-983 (1993)), the cross-reactivity ofpolyclonal antibodies with AD7c-NTP molecule probably occurs throughconformational epitopes. Increased expression of AD7c-NTP was observedin both histologically intact and degenerating neurons and cellprocesses, and a recent study suggested that AD7c-NTP protein expressionoccurs early in AD neurodegeneration.

Example 10 In Vitro Drug Screening System

AD7c-NTP was cloned into a Lac-Switch expression vector (Stratgene), andCYZ neuronal cells were stably transformed with the construct. Severalcell lines were selected that expressed AD7c-NTP at various levels, LacA-Lac F, after induction of protein expression with IPTG. Experimentswere done to determine the effect (e.g., change in morphology, geneexpression, viability, etc.) of AD7c-NTP expression on neuronal cells,thereby generating markers useful for screening, in vitro, potentialpharmacologic agents for the treatment of AD.

Expression levels were determined by Microtiter ImmunCytochemical ElisaAssay (MICE). Briefly, 10⁴ cells/well were seeded into 96-well plates,and were induced to express AD7c-NTP for a period of 6-18 hrs;additionally, in some experiments, cells were exposed to toxins orprotective agents for a similar period of time. At the end the treatmentperiod, cells were fixed, permeabilized and immunostained with theappropriate antibody following the ABS procedure. Quantitation was doneby incubating cells with a soluble chromagen, stopping the reaction with2M H₂SO₄ and determining chromagen absorbance in an automated ELISAreading machine. After staining with Coommassie Blue, the ratio ofimmunoreactivity (i.e. bound chromagen) to Coommassie Blue absorbancewas determined (MICE units), and the results were graphed.Alternatively, immunoreactivity may also be determined with aprecipitating chromagen (e.g. DAB, TruBlue or AEC).

For Experiments determining cell viability, after culture and treatmentas for the MICE assay, culture media was replaced with a CrystalViolet/PBS/formalin solution. After staining, cells were rinsedthoroughly and lysed with a PBS/1% SDS solution, and absorbance wasdetermined with an automated ELSA reader. Results were graphed aspercent viability.

Results: Over-Expression of AD7c-NTP in Neuronal Cells Leads toAlterations in Gene Expression, Cell Viability and ToxinHypersensitivity

Expression of AD7c-NTP results in altered expression of genes associatedwith AD (Tau, bA4 amyloid), neuritic sprouting (synaptophysin) andapoptosis (p53, SC95-Fas, NO-Tyr, NOS3) (FIGS. 7A-7C and 8A-8D). InFIGS. 7A-7C, the percent change in expression, 24 hrs. after AD7c-NTPinduction, is presented for the indicated genes. In the absence ofAD7c-NTP expression (FIG. 7A), little or no change in gene expression isobserved in Lac A-control, nonexpressing cells; however, similarexperiments done with Lac B (FIG. 7B) and Lac F (FIG. 7C) cells inducedto express different levels of AD7c-NTP (B6) demonstrate marked changesin gene expression. For example, NOS3 is expressed at almost twice thenormal level in the Lac B-B6 experiment (FIG. 7B) than in Lac A-controlcells (FIG. 7A).

FIGS. 8A-8D demonstrate that altered gene expression is dependent on thelevel of AD7c-NTP induction. Results are presented for the NTP (FIG.8A), Synaptohysin (FIG. 8B), Tau (FIG. 8C) and p53 (FIG. 8D) genes aspercent change in expression as a function of IPTG induction of AD7c-NTPexpression in stably transfected, CYZ neuronal cells. LacB (filledsquare) and LacF (open circle) cells were exposed to the indicatedamounts of IPTG (1-5 mM) for 24 hrs. These data indicate that increasedconcentrations of IPTG leads to an up-regulation of all genes examined.

Two assays were used to evaluate the effects of AD7c-NTP expression inCYZ neuronal cells: metabolic activity was measured by the MTT assay(FIG. 9A), and cell death was measured by the CV viability assay (FIG.9B). Results are expressed as percent change in MTT activity or cellviability 24 hrs. after IPTG induction relative to untreated, parallelcontrol cultures. Six different clones, LacA-LacF, were assayed afterIPTG induction (B6) and compared to LacA control cells lacking AD7c-NTP.For all 6 clones examined, stimulation of AD7c-NTP expression results insubstantially reduced metabolic activity relative to control cells (FIG.9A). Cell death was induced in LacB-B6 and LacF cells, and reduced cellviability was observed in LacA-B6 and LacE-B6 clones.

Decreased cell viability of cells expressing AD7c-NTP is exacerbated byoxidative stress. When LacB and LacF cells were induced with 3 mM IPTG(B6) for 24 hrs or 48 hrs. and exposed to toxins that increase oxidativestress for 6 hrs or 24 hrs. (FIGS. 10A and 10B, respectively), cellviability decreased markedly as compared to LacA-control, nonexpressingcells. Results depicted in FIGS. 10A and 10B establish both that longerAD7c-NTP induced expression and longer exposure to hydrogen peroxide(H₂O₂) and diethyldithiocarbamic acid (DDC) lead to decreased cellviability and increased hypersensitivity, respectively.

In order to determine the reason for decreased cell viability,experiments were done to quantitatively measure apoptosis in stablytransfected, CYZ neuronal cells expressing AD7c-NTP; results arepresented in FIG. 11. The degree of apoptosis was determined byincubating cells in the presence of ³²dCTP to measuretemplate-independent incorporation of label into fragmented DNA, acharacteristic of the apoptotic mechanism of cell death. Comparison ofcontrol (uninduced, transfected cells) with 3 mM induced (indicated byB6) LacA, LacB and LacF cells clearly indicates that expression ofAD7c-NTP leads to increased incorporation of ³²dCTP label into cellularDNA (increased apoptosis). Variations in the incorporation of labelbetween IPTG induced cell lines are attributed to differences in thelevel of AD7c-NTP expression.

The established in vitro system provides a means for screeningpharmacologic agents that modulate or counteract the changes effectedthrough AD7c-NTP expression and, ostensibly, the AD process. AD7c-NTPexpression leads to up-regulation of nitric oxide synthase which, insome neuronal cells, causes oxygen free radical formation. Theexperiment depicted in FIG. 12 establishes that AD7c-NTP inducedoxidative stress can be counteracted by pharmacologic agents. Resultsare expressed as the ratio of percent change in viability forexperimental (AD7c-NTP induced) over control, uninduced cells. In FIG.12, CYZ cells, stably transfected with AD7c-NTP, are induced to expressAD7c-NTP and exposed to various pharmacologic agents. Hydrogen peroxide(H₂O₂) and diethyldithiocarbamic acid (DDC) exacerbate cell death, whileagents such pyroglutamate (PG) (and L-NAME and L-arginine) inhibit orreduce the nitric oxide synthase toxicity attributable to AD7c-NTPexpression.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions without undue experimentation. All patents, patentapplications and publications cited herein are incorporated by referencein their entirety.

1. A transgenic non-human animal whose germ and somatic cells comprisethe DNA molecule of SEQ ID NO:1 or a DNA molecule which is at least 90%homologous thereto, wherein the DNA molecule of SEQ ID NO:1 or a DNAmolecule which is at least 90% homologous thereto is over-expressed inone or more cells of said transgenic animal, and wherein the DNAmolecule of SEQ ID NO:1 or a DNA molecule which is at least 90%homologous thereto codes for a protein that has an activity of AD7c-NTPwhen over-expressed in neuronal cells.
 2. An in vivo method forscreening a candidate drug that is potentially useful for the treatmentor prevention of Alzheimer's disease, neuroectodermal tumors, malignantastrocytomas, and glioblastomas, said method comprising: (a)administering a candidate drug to the transgenic animal of claim 1, and(b) detecting at least one of the following: (i) the suppression orprevention of expression of the protein coded for by the DNA moleculecontained by said animal; or (ii) the increased degradation of theprotein coded for by the DNA construct contained by said animal; due tothe drug candidate compared to a control animal which has not receivedthe candidate drug.
 3. The transgenic non-human animal of claim 1,wherein said activity of AD7c-NTP possessed by the DNA molecule of SEQID NO:1 or a DNA molecule which is at least 90% homologous thereto whenover-expressed in neuronal cells is selected from the group consistingof neuritic sprouting, nerve cell death, nerve cell degeneration,neurofibrillary tangles and irregular swollen neurites.
 4. An in vivomethod for screening a candidate drug that is potentially useful for thetreatment or prevention of Alzheimer's disease, neuroectodermal tumors,malignant astrocytomas, and glioblastomas, said method comprising: (a)administering a candidate drug to the transgenic animal of claim 1,wherein said transgenic animal exhibits at least one of neuriticsprouting, nerve cell death, degenerating neurons, neurofibrillarytangles, or irregular swollen neurites and axons; and (b) detecting thereduction of frequency of at least one of neuritic sprouting, nerve celldeath, degenerating neurons, neurofibrillary tangles, or irregularswollen neurites and axons in the host due to the drug candidatecompared to a control animal which has not received the candidate drug.5. The method of claim 4, wherein the DNA construct contained by saidanimal has SEQ ID NO:1.
 6. The transgenic non-human animal of claim 1,wherein said transgenic animal is a vertebrate.
 7. The transgenicnon-human animal of claim 1, wherein said transgenic animal is a mammal.